Carl Schroedl

# 000477237

i

THE EFFECT OF VARYING ELECTROLYTIC

CONCENTRATION ON HYDROGEN PRODUCTION

Candidate Name: Carl Schroedl Advisor: Mr. John Pearson

Candidate Number: 000477237 Word Count: 3,997

Category: Chemistry Year: 2008

Center Name: Southwest

Carl Schroedl

# 000477237

ii

Carl Schroedl

# 000477237

i

Abstract

Hydrogen has the potential to wean society off of the expensive and

environmentally detrimental hydrocarbons currently used to meet energy demands.

While proton exchange membranes will be applied in many roles such as

transportation, initial production of hydrogen fuel will come from the electrolysis of

water using alkaline electrolytes.

By applying electrochemical theory and extensive dimensional analysis, an

equation was developed that was thought to describe the relationship between the

molarity of the electrolytic solution and the volume of gas produced in a fixed time.

Many homemade electrolyzer designs were experimented with before settling on one

suitable to the experiment. Sodium hydroxide solutions of varying molarities were

allowed to electrolyze under a eudiometer for 10.0 minutes before the volume of

hydrogen and oxygen gas was recorded.

Although the experimental results did not agree in quantity or in trend with the

relation defined in this paper, foundations of an accurate equation may have been laid.

Appendices include graphics, photographs and discussions of electrolyzers, a

Materials Safety Data Sheet, and suggestions for further research into neglected areas

of science that may soon become significant.

Carl Schroedl

# 000477237

ii

Acknowledgements

The author would like to express gratitude to the following individuals who contributed

significant time, resources, advice, energy or other support to this project:

Sherwood Bergseid: Consultation on ionic mobility

Nathan Ostberg: Preliminary consultation

Kelsey Ostberg: Preliminary consultation, several text books

John Pearson: Laboratory equipment and supervision, text book, consultation,

commenting on successive drafts.

Paul Schroedl: Obtaining stainless steel mesh and other supplies

Tom Zdrazil: Occasional consultation

Access to the 88th

Edition of the CRC Handbook of Chemistry and Physics was provided by

the University of Minnesota’s Walter Library.

Carl Schroedl

# 000477237

iii

Contents Page #

Introduction 1-2

Theory 3-12

Oxidation, Reduction, Anodes and Cathodes 3-5

Electrolytes 3-13

Dissociation 5-6

Alkali Hydroxide Electrolytes 6

Conductivity 6-9

Molar Conductivity 8-9

Relating Conductivity to Gas Production 9-12

Experiment 12-23

Background 12-14

Variables 14-15

Electrolyzer 15-18

Electrolyzer Supplies 15-16

Electrolyzer Construction Procedure 16-18

General Materials 18-19

Procedure 19-21

Data Collection and Representation 21-22

Numerical Analysis 23

Conceptual Analysis 23-24

Conclusion 24

Carl Schroedl

# 000477237

iv

Bibliography 25-26

Appendices 26-48

Appendix A: Extractions from Sources 27-28

Appendix B: Photographs of Constructed Electrolyzers 29-33

Appendix C: Electrolyzer Design 34-39

Appendix D: Materials Safety and Data Sheet of Sodium Hydroxide 40-46

Appendix E: Further Research 48

Carl Schroedl

# 000477237

1

Introduction

Many consider hydrogen to be the environmentally benign fuel of the future.

In August, 2006, the US National Renewable Energy Laboratory determined that

“48% of the worldwide production of hydrogen is via large-scale steam reforming of

natural gas” (“Power” 48). Steam reformation of hydrocarbons produces a bevy of

greenhouse gasses and relies on a resource that dwindles and increases in price.

Exhaustive studies done by the Intergovernmental Panel on Climate Change have

asserted that “Greenhouse gas forcing is the dominant cause of warming during the

past several decades,” and that “It is extremely unlikely (<5%) that recent global

warming is due to internal variability alone” (Hegerl et al 727).

Jeremy Rifkin, the President of the Foundation on Economic Trends, envisions

a future in which hydrogen is produced through a distributed network of electrolyzers

(Rifkin, 218). The prospect of distributed electrolysis using renewable sources of

energy is currently costly, but it may be the route of least environmental impact.

Before the hydrogen economy can be realized, much advancement and research must

be done.

The most promising advancement in both electrolyzer and fuel cell technology

has been the proton exchange membrane (PEM hereafter), which allows for minimal

distances between electrodes and complete product separation. Although much

research is being done in this region of polymer science (“Sandia”, “A Micro”),

Dupount's expensive Nafion® membrane remains the most prevalent.

It is prudent to assume that it will be expensive to purchase fuel cells or any

vehicles powered by them. There will be less incentive to invest in such vehicles if

their accompanying electrolyzers are PEM-based (and therefore expensive). In the

Carl Schroedl

# 000477237

2

introduction of the hydrogen energy epoch, the domestic, distributed production of

hydrogen via electrolysis will be promoted by the PEM's inexpensive alternative:

alkaline electrolytes. Alkali hydroxides receive widespread use as electrolytes

because the compound almost entirely dissociates in water, resulting in an excellent

electrolytic conductor that persists in the solution.

Although most of the alkaline electrolytes used today reside in the alkali

hydroxide category, there is not a consensus on which of these electrolytes is best

suited for the production of hydrogen, nor an equation relating fundamental

electrolyte-specific properties to production. Although potassium hydroxide appears

to be the most frequently employed in large-scale electrolyzers, phrases like, “In the

past, potassium hydroxide was by far the most common electrolyte used,” (Dicks et al,

271) abound throughout sources, providing no further justification. The

concentrations of electrolytic solutions used for water electrolysis were also found to

vary without explanation in sources. This essay utilizes electrochemical theory to

construct an equation relating the volume of gas produced in a fixed amount of time to

the concentration of the sodium hydroxide solution. The equation will be

experimentally verified by constructing an electrolyzer, varying molarity and

observing the volume of gas produced.

Carl Schroedl

# 000477237

3

Theory

As the electrolytic processes required for the production of hydrogen are

complex and interdisciplinary in nature, a thorough explanation of the pertinent theory

must be recounted before any attempt to apply it. To paraphrase Abu Bakr,

knowledge without action is useless and action without knowledge is senseless

(“Sayings”).

Oxidation, Reduction, Anodes and Cathodes

The basic redox reaction that occurs when a current is run through

water is:

222 22 OHOH

This equation represents the overall reaction, not the reactions that occur

locally at each electrode. The electrodes are labeled either cathodes or anodes

depending on whether the electrons are entering or leaving the solution through

them. The nomenclature can be confusing, but the situation can be concretely

established by remembering that cations (positively charged) are always

attracted to cathodes (negatively charged) and anions (negatively charged) are

always attracted to anodes (positively charged.) It is also important to account

for the fact that conventional current is of the opposite sign.

Carl Schroedl

# 000477237

4

The addition of electrons at the cathode causes a reduction reaction to

take place.

OHHeOH 2222 22

The hydroxide ions, being the very definition of an Arrhenius base, contribute

to significant alkalinity at the cathode. An oxidation reaction ensues at the

anode to complete the set of half-reactions.

eHOOH 442 22

At the cathode the water molecules are reduced, producing both

hydrogen, which is attracted to the cathode, and hydroxide ions, whose

negative charges propel them toward the anode. Meanwhile at the anode, the

Cathode ( - ) Anode ( + )

+

+

+

-

-

-

Cation Anion

+ -

Direction of Electron Travel

Power Supply

Alkaline Region Acidic Region

Electrolysis

Carl Schroedl

# 000477237

5

oxidation of water molecules produces oxygen, which is attracted to the anode,

and hydrogen ions, whose positive charges propel them toward the cathode and

the hydroxide ions that it just produced. The cathode’s hydroxides and the

anode’s hydrogen ions react somewhere in between the electrodes, producing

water. For a visual representation of this process, see Appendix B.

Electrolytes

The previous equations neglect the fact that water has preciously few

conductive ions; in pure water at 25° C, hydrgen and hydroxide ions are

present in concentrations of 1×10-7

moles per liter (Pauling, 482). Pure water

has a conductivity of 4.4×10-4

ohm-1

cm-1

at 20° C (Pauling, 517). Water’s

lack of conductivity can be improved through the addition of electrolytes.

Electrolytes increase the quantity of ions available in the solution and hence

decrease the average distance and time for ions produced at the electrodes to

encounter an ion of the opposite charge.

Dissociation

Ionically-bonded compounds dissociate in water. Water has a

dielectric constant of about 80 at room temperature; so two oppositely

charged components of an electrolyte attract each other with 1/80 of the

force that they would in air (Pauling, 434). Additionally, when an

electrolyte is introduced into water, the electrolyte’s cations are

attracted to the slightly negatively-charged (-δ) oxygen atoms of the

water. The electrolyte’s anions are attracted to the water’s slightly

positively-charged (+δ) hydrogen atoms (Dorin et al 548).

Carl Schroedl

# 000477237

6

Some electrolytes dissociate more than others. Strong

electrolytes dissociate more than weak ones. The degree to which

electrolytes dissociate is quantitatively defined by dissociation

constants. The experiments that determine the constants must maintain

constant temperature, pressure and molarity throughout. The values are

difficult to obtain and usually in error of ± 5% (“Solving”).

Alkali Hydroxide Electrolytes

In Fuel Cell Systems Explained, the authors state that, “In

practice… the only electrolytes in use are alkaline liquids and solid

proton exchange membranes” (Dicks et al, 271). Alkali hydroxides and

dissociate completely in water, create only small amounts of metal

buildup on the cathode and emit no toxic gasses at the anode. For

example, when using sodium chloride as an electrolyte, the chloride

anions deposit their extra valence electrons on the anode and are then

bond with other chlorine atoms to form diatomic chlorine gas.

Chlorine gas it is of no use electrolytically and biologically detrimental.

As a consequence of the shortage of anions, sodium metal could also

form on the cathode in this reaction.

Conductivity

Reliable methods of accurately calculating the theoretical

conductivity of electrolytic solutions are the topics of many projects.

Theoretically, individual ions conduct electricity most efficiently per

mole in an infinitely dilute solution of electrolyte. Ions under the

Carl Schroedl

# 000477237

7

influence of the electrodic electric field are also influenced by the

smaller electric fields of the ions of opposite charge.

As an example, assume that an electric field exists between two

electrodes in an aqueous solution containing only one molecule of

monoprotic electrolyte. By chance the dissociated ions start out next to

the electrode of equal charge (i.e. the cation is adjacent to the anode

and vice versa). As the cation is attracted to the cathode, and vice versa,

the electrodic electric field propels the ions across the electrodic gap

and towards each other.

As the ions pass midway between the electrodes they are

attracted to each other, causing them to slow and deviate from their

course. However, the force of attraction between the ions cannot

overcome their attraction to the electrodes and thus they continue on to

their respective electrodes.

+

- anode +

cathode -

1 anode +

cathode -

2

-

anode +

cathode -

4

+

+

-

anode +

cathode -

3

-

+

Actual Path pathpathtravel

Ideal Path

Carl Schroedl

# 000477237

8

The mutual attraction between the ions produced little to no

observable change in the example above, though the reaction would

take place at an exceedingly slow rate; considering that individual ions

in water travel between 10-3

and 10-4

cm s-1

and that they would require

2(6.02×1023

) transversals to produce one mole of hydrogen (“Horiba”).

If the same situation is analyzed using a 1 molar solution of electrolyte,

where every anion is attracted to 6.02×1023

cations and vice versa, the

inter-ionic resistance is much greater. Therefore the most efficient

ionic conduction of electricity per mole occurs when ions are infinitely

dilute.

Molar Conductivity

The variation of the conductivity per mole of electrolyte

with respect to the concentration of the electrolyte was defined

by Kohlrausch to be the following for strong electrolytes:

Where is the molar conductivity at infinite dilution reached

by plotting the molar conductivity at various concentrations

vs. concentration and extrapolating to zero concentration, C is

the concentration of the electrolyte in mol cm-3

and k is the

Kohlrausch coefficient, a constant dependent on the electrolyte

(McCarron). and have units of Ω-1

cm2 mol

-1 and k has

units of cm2L Ω

-1mol

-1.

Carl Schroedl

# 000477237

9

In order to calculate the molar conductivity of a

binary electrolyte at infinite dilution using pre-determined

experimental values, the following formula is needed.

Here both λ terms are ionic molar conductivities, and the

subscripts denote whether they pertain to the cation or anion.

Relating Conductivity to Gas Production

It was noted in the course of background research that there was

a surprising lack of equations devoted to the relation of electrolytic

conductivity to the production of hydrogen and oxygen gas. The

McCarron and Grow resources were particularly helpful in providing

the larger equation’s constituents. To determine the duration of time

required to produce a certain volume of hydrogen and oxygen gas when

voltage is known, pressure is standard, and temperature is 298K, a

preliminary equation that draws on the stoichiometric coefficients of

the reaction, the Ideal Gas Law, the Faraday constant and the relation

of electrical quantities must be used. It is less complicated to calculate

the number of moles in 1.00 L of ideal gas at 298K and standard

pressure before considering the main preliminary equation.

RT

PVn

V=Volume, n=number of moles, R=Ideal Gas Constant,

T=Temperature, P=Pressure

Carl Schroedl

# 000477237

10

mol

KmolK

atmL

Latmn 041.0

298082058.0

00.100.1

Substituting this crucial volume, it is possible to make a preliminary

equation. Note that gas refers to both hydrogen and oxygen gasses and

that the Faraday constant is the charge on a mole of electrons defined as

follows:

e

CF

1

10602.1

e mol 1

e 106.02

e mol 1

C 96485.34 19

-

-23

-

Preliminary Equation:

sec C

sec

e mol 1

C 96485.34

gas mol 3

e mol 2

gas L 1

gas mol 0.041gas Lin V

-

t

The only number lacking in this preliminary equation is the amperage.

The amount of current flowing is dependent on the conductivity

equations mentioned earlier. Consider the following equations once

more:

Once the molar conductivity of an electrolyte is known, this quantity

can be used to find the conductivity ( ) of the electrolytic solution of a

known concentration C in mol cm-3

.

Cc

When the equation is solved for κ, κ’s remaining units provide a

revealing path to the resistance that the electrolytic solution produces in

an electrolyzer’s circuit.

Carl Schroedl

# 000477237

11

3

2

ccm

molin C

Ωmol

cmin Λ

Ωcm

1in κ

The conductivity ( ) is the reciprocal of the solution’s resistivity (ρ).

RA

d

1

The variables d, the gap between electrodes, and A, the electrodic

parallel surface area, relate κ to resistance (R), a volume-dependent

quantity. When R is solved for using dimensional analysis, it can be

shown that the units cancel, and only resistance in ohms remains.

Ωin Rcm

cmΩ

Ω cm

cm d

cmA cmΩin κ

cm dΩin R

1-21-1-

If a known constant voltage is being applied across the electrodes, the

current passing through the solution can be found by substituting R into

the simple equation that relates current, resistance and voltage.

Ohms R

Volts EAmps I

Since the ampere is defined as one Coulomb per second, substituting

the output of the previous equation into the preliminary equation should

provide a method of determining the time required to produce a given

amount of gas as the concentration of the electrolyte varies. The entire

relation of electrolytic concentration ( M in mol L-1

) to the number of

seconds ( t ) required to produce a volume of gas follows. All included

variables were defined above.

Relation of Electrolytic Concentration to Time:

Carl Schroedl

# 000477237

12

sec

Cin

1010

sec

e mol 1

C 96485.34

gas mol 3

e mol 2

gas L 1

gas mol 0.041gas Lin V

36

3

336

3

32

22

0

2

-

t

cmd

cm

m

m

L

L

molM

cm

m

m

L

L

molM

mol

Lcmk

mol

cmAcm

voltsVc

It is experimentally easier to verify to volume of gas produced

via electrolysis in a known time than it is to measure how the length of

time required to generate a given volume of gas. By algebraic

manipulation of the preceding equation, the equation is solved for

volume as follows.

Relation of Electrolytic Concentration to Product Volume:

gas Lin Vgas mol 0.041

gas L 1

e mol 2

gas mol 3

34.96485

e mol 1

sec

Cin

1010

sect -

36

3

336

3

32

22

0

2

C

cmd

cm

m

m

L

L

molM

cm

m

m

L

L

molM

mol

Lcmk

mol

cmAcm

voltsVc

Experiment

Background

Using electrochemical knowledge described in the Theory section as

well as constants obtained from Grow and McCarron, this experiment attempts

to verify aforementioned relation of concentration to time by electrolyzing an

electrolytic solution of known concentration and measuring the time required

to produce 50 ml of gas. Several home-made electrolyzers were built and it

was eventually decided that gas separation should be sacrificed for a narrower

electrode gap in order to reduce the time needed to produce measureable

volumes of gas. A summary of electrolyzer design considerations and

alternate designs are included in Appendix C. Sodium hydroxide was chosen

Carl Schroedl

# 000477237

13

as the electrolyte because it was the most economically accessible of the alkali

hydroxides, whose benefits were mentioned earlier.

The constants required by the large equation were obtained either by

direct measurement or from credible sources. The area (A) and electrode gap

(d) were measured with a ruler. McCarron provided the values of 0 and

0

at 298 K in12 molm . After converting to Ω

-1 cm

2 mol

-1, the limiting molar

ionic conductivities of the sodium cation and the hydroxide anion are

(respectively): 1210 2.50

molcm 1210 6.197 molcm

Using these two variables, and the equation , Λ0 was calculated.

121121121

0 8.2476.1972.50 molcmmolcmmolcm

It was difficult to find values of the Kohlrausch coefficient ( k ). The

slope of a graph (see Appendix A) of the molar conductivity of NaOH over the

square root of its concentration was used to determine k :

0.5 672

mol

Lcmk

The imprecision of this constant could be the source of some future

discrepancies in experimental results, but no other method was available.

Further research and publication of Kohlrausch coefficients should be

encouraged.

A constant voltage was selected with the interest of both reaction rate

and efficiency in mind. Fuel Cell Systems Explained suggests that the

efficiency ( ) of an electrolyzer should be roughly defined by relating the

Carl Schroedl

# 000477237

14

theoretical minimum voltage (1.48 V) required by the reaction to Vc, the

voltage being used in practice (Dicks et al 273).

cV

48.1 V

VVc 96.2

50.0

48.1

A target efficiency of 50%, or rather 2.96 V was judged to produce an

acceptable rate of reaction.

The production of gas over water should consider the partial pressures

of water vapor to see how it affects the volume of the gas. When the

eudiometer is lifted or lowered so that the internal waterline is at the external

waterline, it is ensured that the pressure is equal to that of the atmosphere. The

variation of the pressure inside the eudiometer will be ±5%; the local pressure

may be slightly different than 1.0 atm and the eudiometer cannot be held in a

very precise position. The pressure’s significant figures cause the water

vapor’s addition to the volume collected inside the eudiometer to be negligible.

Variables

The molarity of the solution will be the manipulated variable. The

responding variable will be the volume of gas produced in 600 sec (10 min).

The experiment will take place with a constant pressure of approximately 1.0

atm and a temperature of 298 K. The following constants will be assumed:

0.01 96.2 VVc 0.5 672

mol

Lcmk A = 7.1cm

2±0.1 d = 0.1cm±0.05

The values of constants Vc and k are discussed in previous sections. The value

of A is the parallel surface area of the electrodes (or simply width×length of

Carl Schroedl

# 000477237

15

one electrode assuming they are the same size) and d is the gap between the

electrodes.

Hypothesis

Assuming constant pressure, temperature, Kohlrausch coefficient,

parallel electrodic surface area, electrodic gap, and molar conductivity, all of

which have been given values in the Variables section, the volume of gas

produced in 10 minutes via the water electrolysis of an electrolytic solution of

sodium hydroxide will vary with the molarity of the solution according to the

equation:

Lin Vgas mol .041

gas L 1

e mol 2

gas mol 3

34.96485

e mol 1

sec

1.0

1010678.2471.7

96.2

sec 600-

36

3

336

3

32

222

C

Ccm

cm

m

m

L

L

molM

cm

m

m

L

L

molM

mol

Lcm

mol

cmcm

volts

Due to the relatively inexpert construction of the electrolyzer, the results are

not expected to match the values of the equation, but should reflect the general

trend.

Electrolyzer

Electrolyzer Supplies

1 cylindrical plastic container with a capacity of 1 L

25 cm2 of stainless steel mesh with 5.5 wires cm

-1 as measured on

an edge as in diagram

15 cm2 fiberglass mesh with 5.5 wires cm

-1

Carl Schroedl

# 000477237

16

Hot glue gun, glue

1 metal rod whose length is twice the container’s height and whose

diameter is between 0.5 and 3 centimeters

Small, angled razor

1 pair of sharp shearers

Electrolyzer Construction Procedure

Measure the inner diameter (ID) of the eudiometer being used.

Cut two strips of metal mesh, each with the dimensions 10cm (ID -

0.1 cm) so that the electrodes slide in and out of the eudiometer. It may

help to straighten the wire mesh before continuing. Bend 2 cm on the

end of the mesh strip so that it is perpendicular to the main length of

electrode. Cut out one strip of fiberglass mesh with the same

dimensions as the stainless steel mesh. Sandwich the fiberglass

between the two electrodes, arranging the electrodes as in the assembly

diagram below. Most hot glue guns should be plugged in now. Ensure

that the electrodes make no direct contact. A multimeter with a circuit

continuity tester can ensure this when a probe is placed on either

electrode. Holding this assembly together, insert it into the eudiometer

that will be used. If it will not fit, trim as needed.

Add hot glue to the tip of the electrodes and at the T-shaped

juncture as depicted in diagram. While the glue cools, cut a small

rectangular slit into the center of the bottom of the container. The slit

should be just wide enough for the electrodes to pass through. Once

Carl Schroedl

# 000477237

17

the glue on the electrodes cools, insert the electrodes through the slit

and turn the container’s bottom upwards.

Hot glue the area where the container meets the electrodes,

ensuring that the electrodes will be perpendicular to the bottom of the

container. After the glue cools, trim any excess fiberglass mesh

hanging from the bottom. Flip the container. Apply hot glue to the tip

of the long rod. Quickly use the rod’s hot glue to seal the area where

the electrodes meet the container. The glue will cool quickly. Remove

the glue and apply fresh hot glue as needed. Let cool. Test to see if the

seal is complete by filling the container with water and resting it on a

cup and waiting one hour. If an appreciable volume of water has

accumulated in the cup after an hour, additional coatings of glue should

be applied as defined above.

Carl Schroedl

# 000477237

18

General Materials

Electrolyzer (see above)

130 g NaOH

8 L deionized water

Electronic balance

1 Weight boat

1 Graduated eudiometer with capacity of 100 ml

1 Stopper for mentioned eudiometer

1 Pair of thick rubber gloves

4 Large rubber stoppers

1 Multimeter accurate to the mV

Stainless steel mesh

Fiberglass mesh

Hot glue

Assembly Diagram

Container

Solution

Waterproof Seal

Carl Schroedl

# 000477237

19

1 10-Ampere power supply with variable potential (2.96 V D.C. desired).

2 Scoopulas for handling NaOH

1 Test tube brush with handle longer than eudiometer’s length

8 Beakers, each with a capacity of 1 L (less beakers is permissible, but will

require more rinsing)

Stopwatch

Access to tap water

Medium gauge copper wire

1 water container at least as tall as the eudiometer and wide enough for a

clenched fist to pass through.

Procedure

Warning: Sodium hydroxide is caustic and dangerous if handled improperly.

Consult the Materials Safety Data Sheet in Appendix D before continuing.

Wear gloves, apron and goggles to prevent injury. Hydrogen and Oxygen

form an explosive mixture. Do not experiment near open flame.

The barometric pressure and temperature should be tested at the

location before starting experiment. If any values differ by more than 5%,

consider another day, or readjust equation constants. Use the electronic

balance, the scoopulas, large beakers, deionized water and sodium hydroxide

to produce two 1 liter solutions for each of the following concentrations (mol

L-1

): 0.01 M, 0.1 M, 0.5 M, and 1.0 M. Cover each filled beaker to maintain

purity. Fill the tall, narrow container with tap water. Fasten or solder wire to

the extensions of the electrodes underneath the container. Prevent a short

Carl Schroedl

# 000477237

20

circuit by using the four large stoppers to support the container throughout the

trials. Connect the loose ends of the wires to the power supply. Set the power

supply’s potential to 2.96 V. Turn off the power supply. Repeat the following

numbered steps, varying the molarity in the following order: 0.01 M, 0.1 M,

0.5 M, 1.0 M, 0.01 M, 0.1 M, 0.5 M, and 1.0 M

1. Pour the solution of selected concentration into the electrolyzer until

the water level is at least 1 cm above the top of the electrodes. Overfill

the eudiometer with the remainder of the solution.

2. Seal the end of the eudiometer using a thumb or a stopper.

3. Invert the eudiometer and ensure that no bubbles rise to the top. If they

do, return the eudiometer to its former orientation, add more solution,

close the end and repeat this step until no bubbles rise.

4. Place the mouth of the eudiometer underneath the fluid level of the

electrolyzer and release the stopper or thumb. Raise the mouth above

the electrode height, but below the fluid level. Lower the eudiometer

until it rests on the electrodes’ base.

5. Turn on the power supply and start the stopwatch simultaneously. Wait

10 minutes.

6. After 10 minutes, turn off power supply. Allow 2 minutes for the gas

bubbles to collect in the top of the eudiometer. Tap and/or jostle the

eudiometer to dislodge the bubbles.

7. Repeat step 2.

Carl Schroedl

# 000477237

21

8. Transfer to tall, narrow container. Release the stopper underwater.

Raise or lower the eudiometer until the level of the solution within

equals the outer water level.

9. Record the volume on a table next to the molarity of solution used.

10. It is safe in most localities to dump the range of concentrations used in

this investigation into the sanitary sewer. Check your local guidelines

and then dump out the solution from the electrodes’ container and

eudiometer. Rinse the electrodes and the involved containers

thoroughly, preferably with pressurized water.

Data Collection and Representation

Trial Molarity (mol/L)

Error (+/-

mol/L)

Volume of Gas (L)

Error (+/- L)

Comments Average

Volume (L) Error of Average Volume (+/-L)

1 0.01 0.002 0.0052 0.0004 unable to equalize

inner and outer fluid levels

0.0062 0.0004 2 0.01 0.002 0.0072

1 0.10 0.002 0.0432 0.0001

0.0447 0.0001

2 0.10 0.002 0.0461

1 0.50 0.002 0.0846 0.0001

0.0815 0.0001

2 0.50 0.002 0.0784

1 1.00 0.002 0.0954 0.0001

0.0940 0.0001

2 1.00 0.002 0.0926

Carl Schroedl

# 000477237

22

Volume of Gas vs. Molarity

0.01 ± 0.002, 0.0062 ±

0.0004

0.10 ± 0.002, 0.0447± 0.0001

0.50 ± 0.002, 0.0815 ±

0.0001

1.00 ±0.002, 0.0940 ± 0.0001

y = 0.0193Ln(x) + 0.0933

R2 = 0.9949

0.0000

0.0100

0.0200

0.0300

0.0400

0.0500

0.0600

0.0700

0.0800

0.0900

0.1000

0.00 0.20 0.40 0.60 0.80 1.00

Molarity (mol/L)

Vo

lum

e (

L)

Average Volume of Gas (L) Logarithmic Regression

Error bars were added to each point, but their presence is difficult to discern.

Theoretical and Experimental Comparison

y = 0.0193Ln(x) + 0.0933

R2 = 0.9949

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0 0.2 0.4 0.6 0.8 1

Concentration (mol/L)

Vo

lum

e (

L)

f(x)=600*(2.96*((7.1*(247.8-67*SQRT(x/1000000))*(x/1000000))/0.1))*(1/96485.34)*(3/2)*(1/0.041) in L

Experimental Volume (L)

Logarithmic Regression

Carl Schroedl

# 000477237

23

Numerical Analysis

The experimental data is linearly approximated on the interval of .01 M

- 1.0 M by the equation y = 0.0787x + 0.0249 where R2 = 0.8063. For the

concentrations dealt with in this experiment, the pictured logarithmic

approximation (y = 0.0193Ln(x) + 0.0933) is much more accurate (R2 =

0.9949). The linear equivalent (R2=1) of the proposed equation was found to

be y = 2E-05x + 6E-10 on the same interval, while an accurate logarithmic

approximation could not be found.

Conceptual Analysis

The gradual buildup of sodium on the cathode could have influenced

results, but observations and precautions taken in the experiment should have

minimized this impact. A visual inspection of the electrodes before each trial

did not discover any difference in between trials. Additionally, the electrodes

were rinsed with a high-pressure jet of water after every trial. The results of

the second trials were not consistently greater or smaller than the first trials.

The experimental results seem more conceptually valid than the results

predicted by the equation. If the proposed equation were correct, it still

wouldn’t account for electrolyzer inefficiencies. Therefore, the volume

produced would always be less than the expected. As the results produce more

than theoretically possible, the equation’s accuracy is doubtful. The equation

should be a logarithmic or root function; every instance molarity is increased,

the molar conductivity decreases. The volume should also decrease as the

Carl Schroedl

# 000477237

24

molarity of the solution approaches the solubility of the electrolyte in water

because undissociated electrolytes would likely have a high dielectric constant.

Conclusion

Presently the experimental data does not match the proposed relation of gas

volume to concentration in value or in shape in the interval of 0.01 M - 1.0 M. The

hypothesis must be rejected because the volumes produced do not closely match the

shape of the proposed equation. The error in the equation doubtlessly lies in the

complicated numerator. Some error may have occurred in the conversion to electrical

impedance. Although the suggested model is inaccurate, it may prove to be a useful

base for further research (See Appendix E) into this worthy area of electrochemistry.

Carl Schroedl

# 000477237

25

Bibliography

Brown, Theodore; Bursten, Bruce; LeMay, H.; Murphy, Catherine. Chemistry: The Central

Science. Pearson Education Inc. Upper Saddle River, New Jersey. 2006.

CRC. The Handbook of Chemistry and Physics. CRC Press. Cleveland, OH. 2007.

Dicks, Andrew; Larminie, James Fuel Cell Systems Explained. John Wiley & Sons Ltd.

West Sussex, England. 2003.

Dorin, Henry; Demmin, Peter; Gabel, Dorothy. Chemistry: The Study of Matter. Prentice-

Hall, Incorporated. Needham, Massachusetts. 1989

Egel, Geoff “IceStuff.com: Build your own own …”

http://www.icestuff.com/~energy21/electrolysis.htm 8/15/07

Faraday, Hittorf, Kohlrausch “The fundamental laws of electrolytic conduction…”

http://www.openlibrary.org/details/fundamentallawso00goodrich 12/20/07

Grow, James M. “Conductivity of Electrolytic Solutions” http://www-

ec.njit.edu/Electrochemistry 8/22/07

“The Hartee-Fock Method” http://www.chm.bris.ac.uk/pt/harvey/elstruct/hf_method.html

8/19/07

“Horiba: The Story of Conductivity”

http://www.jp.horiba.com/story_e/conductivity/conductivity_03.htm 8/21/07

Hamereli, Gabriele; Zwiers, Francis et al “Understanding and Attributing Climate Change”

http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch09.pdf 11/29/07

“Ionization Energy” http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/ionize.html#c1

8/19/07

McCarron, Tanner. “Tanner’s General Chemistry.” http://www.tannerm.com/ 24/11/2007

“A Micro Hydrogen Air Fuel Cell” http://stinet.dtic.mil/cgi-

bin/GetTRDoc?AD=ADA440192&Location=U2&doc=GetTRDoc.pdf 08/23/07

“MSDS Search” http://www.mallbaker.com/Americas/catalog/default.asp?searchfor=msds

12/22/07

“Nafion Acidity” http://www.permapure.com/TechNotes/Nafionacidity.htm 8/22/07

Pauling, Linus. General Chemistry. Dover Publications. Mineola, New York. 1988

Carl Schroedl

# 000477237

26

“Over Unity Power” http://www.oupower.com 8/20/07

“Power Technologies Energy Data Book”

http://www.nrel.gov/analysis/power_databook/docs/pdf/39728_complete.pdf 8/22/07

Rifkin, Jeremy. The Hydrogen Economy. Jeremy P. Tarcher/Penguin. New York. 2003.

“Sandia polymer electrolyte membrane …” http://www.sandia.gov/news-center/news-

releases/2004/renew-energy-batt/microfuel.html 8/22/07

“Sayings of Abu Bakr” http://muslim-canada.org/sayingsabubakr.html#knowledge 8/19/07

Shermer, Michael. Why People Believe Weird Things. Henry Holt and Company. New York.

2002.

“Sodium: History” http://nautilus.fis.uc.pt/st2.5/scenes-e/elem/e01110.html 1/03/08

“Solving Weak Base Problems” http://www.dbhs.wvusd.k12.ca.us/webdocs/AcidBase/Kb-

Solving1.html 8/23/07

Carl Schroedl

# 000477237

27

Appendix A: Extractions from Sources

Extraction from Linus Pauling’s General Chemistry

pg. 518

Carl Schroedl

# 000477237

28

Extraction from Grow’s Webpage

Use Kohlrausch’s equation:

The molar conductivity at infinite dilution is known to be 247.8. The concentration and molar

conductivity of the rightmost point on the line above can be estimated. The equation can be

solved for the variable k. 24.18.247150 k

k=67

~250

~150

~1.40

Carl Schroedl

# 000477237

29

Appendix B

Photographs of Constructed Electrolyzers

“U” Model

Carl Schroedl

# 000477237

30

Two-Bottle Model

The layer on top is hydrogen gas.

Carl Schroedl

# 000477237

31

ABS pipe caps added to weigh down bottles and prevent them from shifting away from

parallel.

Carl Schroedl

# 000477237

32

Flex Model

Flex and Two-Bottle Models.

Mesh was wrapped around tubing to maintain shape.

Carl Schroedl

# 000477237

33

Early Sandwich Model

Carl Schroedl

# 000477237

34

Appendix C: Electrolyzer Design

Electrolyzer Design

The main considerations in electrolyzer design are gas separation, parallel electrode

surface area, electrode distance and current density. Separation of the product gasses is

crucial because if cross-contamination occurs, a very explosive mixture results. This mixture

is not useful when used in fuel cells. In electrolyzers, and in general, electricity takes the path

of least resistance, which, barring some form of insulation, is the shortest path available.

Decreasing the distance between the electrodes decreases resistance. Increasing the surface

area of both electrodes allows increased amperage. Voltage supplied to the electrolytic

solution need only be in the range of 1.48 to 2.0 volts according to the standard reduction

potential of water (Pauling 529, Dicks et al 273).

Many different electrolyzer designs exist. A very common demonstration model is

known as the Hoffman apparatus. The device is constructed of three thin glass tubes, two

electrodes, two stopcocks, and a bulbous electrolyte addition area. These models are

expensive, and not very efficient, but their transparency allows students to view the reaction

take place. The main cost associated with this design, indeed with many designs, is the

platinum electrodes. Platinum is ranks high in terms of nobility and thus is less likely to

degrade during the reaction. Platinum is also a good conductor. The delicate glassware

associated with Hoffman apparatuses is costly as well.

Carl Schroedl

# 000477237

35

Although porous platinum electrodes improve the efficiency of the process, the long,

non-linear path that the electricity must travel provides extensive resistance. One advantage

of the design is that the gasses are fully separated. Another advantage that the Hoffman

electrolyzer has is the fact that, because water is virtually incompressible, the gas is

compressed and can be released directly into a high-pressure storage tank. Of course, if the

gas pressure was allowed to build up too high, the glass shards of the resulting explosion

would be a hazard to anything nearby.

To promote distributed generation, electrolyzers should be neither dangerous

nor expensive. In fact, medium-scale electrolyzers are not difficult to construct. In

homemade devices, electrical energy could be supplied to electrolyzers via a standard ATX

computer power supply if the sense wire (pin 14 on MOLEX connector) were shorted to

Carl Schroedl

# 000477237

36

ground and a small load were attached. The load could take the form of a large resistor or

spare computer device, such as an optical or hard drive. Newer power supplies have multiple

+3.3 volt, high amperage wires that could be attached to the electrodes in parallel for

electrolysis.

Several homemade designs have surfaced on the internet that favor a devices whose

appearances are akin to the letters “E” and “U” (Egel, “Over”). Devices favor

polyvinylchloride (PVC) pipes or tubing because of the ubiquity, inexpensiveness and non-

interfering nature of the material. The E-shaped devices are similar to the Hoffman

electrolyzer, and consequently suffer from the same inefficiencies of imprudent electrode

placement; the closer the electrodes are placed, the more likely that products will mix and

escape through the central column. The U-shaped electrolyzers allow for narrower electrode

gaps, but makes gas separation more difficult. Both designs are able to pressurize the reaction

products. Neither design maintains the transparency of the Hoffman electrolyzer, unless clear

PVC pipe is used. At the time of writing, clear PVC pipe was expensive at local and online

retailers. Homemade electrodes are made of relatively inexpensive stainless steel mesh.

Mesh has a high surface area to volume ratio and is usually hand-malleable so that those

without machining experience or equipment can construct the devices as well. The “U”

model was the first constructed in this investigation.

Carl Schroedl

# 000477237

37

Another homemade design conceived and constructed in this study takes advantage of

even more widely-available materials. Two modified plastic soft drink containers can be used

as the outer walls of the device. Barbed hose connectors are secured to each bottle cap via

washer and nut. Approximately 90° of each bottle’s circumference is removed along its flat

vertical length (see diagram). The stainless steel mesh electrodes are fixed inside each bottle

with a stainless steel screw. Copper leads to the power supply are wrapped around the screws

and waterproofed with hot glue to prevent oxidation. The bottles are placed inside of a

slightly larger container. Once the electrolytic solution has been added to the larger container,

the bottles are inserted and allowed to fill. Afterwards, the bottles are oriented towards each

other to maximize the amount of parallel electrode surface area.

Carl Schroedl

# 000477237

38

The Two-Bottle Model was effective, but suffered from a few defects. The large

parallel surface area of the electrodes was partially negated by the electrode gap. The gap,

however, was actually too narrow, because it was observed that a slight cross-contamination

of the gasses took place. The gas can be pressurized by this electrolyzer, as long as the level

of gas remains above the electrodes and the cut-out portion of the wall. Provided that labels

are removed form the bottles and that the larger container is transparent, the process is clearly

visible. If the junction between screw and copper wire is not shielded from the electrolytic

solution, the metals begin to oxidize and slowly lose conductivity until the reaction comes to a

Carl Schroedl

# 000477237

39

standstill. As the volume of water is comparatively enormous, the waterline is not visibly

reduced, even after 12 hours of continuous electrolysis at high amperage.

In order to decrease the total volume of water needed and separate the gasses more

effectively, a third design was created. The container for the electrolytic solution was arrow,

flexible, transparent PVC tubing. The tubing was inexpensive when purchased from a local

hardware retailer. The tubing was bent into a “U” shape and held in place by tying sections of

it to a regularly-punctured display board. The electrodes consisted of rolled stainless steel

mesh. It would be difficult to seal any direct copper connection to the mesh, so a short

segment of single-strand stainless steel wire was used as an intermediary. The intermediary

may not have been sufficiently wide or conductive and consequently may have acted as a

resistor to the large current flow. Unfortunately, the small diameter of the tube requires

considerably reduced parallel electrode surface area. The gas separation was the most

complete out of all the constructed devices, because the distance between the electrodes could

be easily adjusted. It can be reasonably assumed that in both the Flex and “U” Models the

electrode gap could be decreased if a membrane were placed in between them. In lieu of a

more advanced membrane, a common sponge could be used in future trials where large gas

output and product separation is desired.

Gas separation was deemed unnecessary for the purposes of the main experiment

given the inconvenience of slow reaction rate. The sandwich model was created. It is

detailed in the Electrolyzer Section of the main paper.

Carl Schroedl

# 000477237

40

Appendix D: Materials Safety and Data Sheet of Sodium Hydroxide

Obtained via http://www.mallbaker.com/Americas/catalog/default.asp?searchfor=msds

SODIUM HYDROXIDE

1. Product Identification

Synonyms: Caustic soda; lye; sodium hydroxide solid; sodium hydrate

CAS No.: 1310-73-2

Molecular Weight: 40.00

Chemical Formula: NaOH

Product Codes: J.T. Baker: 1508, 3717, 3718, 3721, 3722, 3723, 3728, 3734, 3736, 5045, 5565

Mallinckrodt: 7001, 7680, 7708, 7712, 7772, 7798

2. Composition/Information on Ingredients

Ingredient CAS No Percent

Hazardous

--------------------------------------- ------------ ------------ -

--------

Sodium Hydroxide 1310-73-2 99 - 100%

Yes

3. Hazards Identification

Emergency Overview --------------------------

POISON! DANGER! CORROSIVE. MAY BE FATAL IF SWALLOWED. HARMFUL

IF INHALED. CAUSES BURNS TO ANY AREA OF CONTACT. REACTS WITH

WATER, ACIDS AND OTHER MATERIALS.

SAF-T-DATA(tm)

Ratings (Provided here for your convenience)

-----------------------------------------------------------------------------------------------------------

Health Rating: 4 - Extreme (Poison)

Flammability Rating: 0 - None

Carl Schroedl

# 000477237

41

Reactivity Rating: 2 - Moderate

Contact Rating: 4 - Extreme (Corrosive)

Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT HOOD;

PROPER GLOVES

Storage Color Code: White Stripe (Store Separately)

-----------------------------------------------------------------------------------------------------------

Potential Health Effects ----------------------------------

Inhalation: Severe irritant. Effects from inhalation of dust or mist vary from mild irritation to serious

damage of the upper respiratory tract, depending on severity of exposure. Symptoms may

include sneezing, sore throat or runny nose. Severe pneumonitis may occur.

Ingestion: Corrosive! Swallowing may cause severe burns of mouth, throat, and stomach. Severe

scarring of tissue and death may result. Symptoms may include bleeding, vomiting, diarrhea,

fall in blood pressure. Damage may appear days after exposure.

Skin Contact: Corrosive! Contact with skin can cause irritation or severe burns and scarring with greater

exposures.

Eye Contact: Corrosive! Causes irritation of eyes, and with greater exposures it can cause burns that may

result in permanent impairment of vision, even blindness.

Chronic Exposure: Prolonged contact with dilute solutions or dust has a destructive effect upon tissue.

Aggravation of Pre-existing Conditions: Persons with pre-existing skin disorders or eye problems or impaired respiratory function may

be more susceptible to the effects of the substance.

4. First Aid Measures

Inhalation: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give

oxygen. Call a physician.

Ingestion: DO NOT INDUCE VOMITING! Give large quantities of water or milk if available. Never

give anything by mouth to an unconscious person. Get medical attention immediately.

Skin Contact: Immediately flush skin with plenty of water for at least 15 minutes while removing

contaminated clothing and shoes. Call a physician, immediately. Wash clothing before reuse.

Eye Contact: Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper

eyelids occasionally. Get medical attention immediately.

Carl Schroedl

# 000477237

42

Note to Physician: Perform endoscopy in all cases of suspected sodium hydroxide ingestion. In cases of severe

esophageal corrosion, the use of therapeutic doses of steroids should be considered. General

supportive measures with continual monitoring of gas exchange, acid-base balance,

electrolytes, and fluid intake are also required.

5. Fire Fighting Measures

Fire: Not considered to be a fire hazard. Hot or molten material can react violently with water.

Can react with certain metals, such as aluminum, to generate flammable hydrogen gas.

Explosion: Not considered to be an explosion hazard.

Fire Extinguishing Media: Use any means suitable for extinguishing surrounding fire. Adding water to caustic solution

generates large amounts of heat.

Special Information: In the event of a fire, wear full protective clothing and NIOSH-approved self-contained

breathing apparatus with full facepiece operated in the pressure demand or other positive

pressure mode.

6. Accidental Release Measures

Ventilate area of leak or spill. Keep unnecessary and unprotected people away from area of

spill. Wear appropriate personal protective equipment as specified in Section 8. Spills: Pick

up and place in a suitable container for reclamation or disposal, using a method that does not

generate dust. Do not flush caustic residues to the sewer. Residues from spills can be diluted

with water, neutralized with dilute acid such as acetic, hydrochloric or sulfuric. Absorb

neutralized caustic residue on clay, vermiculite or other inert substance and package in a

suitable container for disposal.

US Regulations (CERCLA) require reporting spills and releases to soil, water and air in

excess of reportable quantities. The toll free number for the US Coast Guard National

Response Center is (800) 424-8802.

7. Handling and Storage

Keep in a tightly closed container. Protect from physical damage. Store in a cool, dry,

ventilated area away from sources of heat, moisture and incompatibilities. Always add the

caustic to water while stirring; never the reverse. Containers of this material may be

hazardous when empty since they retain product residues (dust, solids); observe all warnings

Carl Schroedl

# 000477237

43

and precautions listed for the product. Do not store with aluminum or magnesium. Do not mix

with acids or organic materials.

8. Exposure Controls/Personal Protection

Airborne Exposure Limits: - OSHA Permissible Exposure Limit (PEL):

2 mg/m3 Ceiling

- ACGIH Threshold Limit Value (TLV):

2 mg/m3 Ceiling

Ventilation System: A system of local and/or general exhaust is recommended to keep employee exposures below

the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can

control the emissions of the contaminant at its source, preventing dispersion of it into the

general work area. Please refer to the ACGIH document, Industrial Ventilation, A Manual of

Recommended Practices, most recent edition, for details.

Personal Respirators (NIOSH Approved): If the exposure limit is exceeded and engineering controls are not feasible, a half facepiece

particulate respirator (NIOSH type N95 or better filters) may be worn for up to ten times the

exposure limit or the maximum use concentration specified by the appropriate regulatory

agency or respirator supplier, whichever is lowest.. A full-face piece particulate respirator

(NIOSH type N100 filters) may be worn up to 50 times the exposure limit, or the maximum

use concentration specified by the appropriate regulatory agency, or respirator supplier,

whichever is lowest. If oil particles (e.g. lubricants, cutting fluids, glycerine, etc.) are present,

use a NIOSH type R or P filter. For emergencies or instances where the exposure levels are

not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air-

purifying respirators do not protect workers in oxygen-deficient atmospheres.

Skin Protection: Wear impervious protective clothing, including boots, gloves, lab coat, apron or coveralls, as

appropriate, to prevent skin contact.

Eye Protection: Use chemical safety goggles and/or a full face shield where splashing is possible. Maintain

eye wash fountain and quick-drench facilities in work area.

9. Physical and Chemical Properties

Appearance: White, deliquescent pellets or flakes.

Odor: Odorless.

Solubility: 111 g/100 g of water.

Specific Gravity:

Carl Schroedl

# 000477237

44

2.13

pH: 13 - 14 (0.5% soln.)

% Volatiles by volume @ 21C (70F): 0

Boiling Point: 1390C (2534F)

Melting Point: 318C (604F)

Vapor Density (Air=1): > 1.0

Vapor Pressure (mm Hg): Negligible.

Evaporation Rate (BuAc=1): No information found.

10. Stability and Reactivity

Stability: Stable under ordinary conditions of use and storage. Very hygroscopic. Can slowly pick up

moisture from air and react with carbon dioxide from air to form sodium carbonate.

Hazardous Decomposition Products: Sodium oxide. Decomposition by reaction with certain metals releases flammable and

explosive hydrogen gas.

Hazardous Polymerization: Will not occur.

Incompatibilities: Sodium hydroxide in contact with acids and organic halogen compounds, especially

trichloroethylene, may causes violent reactions. Contact with nitromethane and other similar

nitro compounds causes formation of shock-sensitive salts. Contact with metals such as

aluminum, magnesium, tin, and zinc cause formation of flammable hydrogen gas. Sodium

hydroxide, even in fairly dilute solution, reacts readily with various sugars to produce carbon

monoxide. Precautions should be taken including monitoring the tank atmosphere for carbon

monoxide to ensure safety of personnel before vessel entry.

Conditions to Avoid: Moisture, dusting and incompatibles.

11. Toxicological Information

Irritation data: skin, rabbit: 500 mg/24H severe; eye rabbit: 50 ug/24H severe; investigated as

a mutagen. --------\Cancer Lists\---------------------------------------------------

---

Carl Schroedl

# 000477237

45

---NTP Carcinogen---

Ingredient Known Anticipated IARC

Category

------------------------------------ ----- ----------- ----------

---

Sodium Hydroxide (1310-73-2) No No None

12. Ecological Information

Environmental Fate: No information found.

Environmental Toxicity: No information found.

13. Disposal Considerations

Whatever cannot be saved for recovery or recycling should be handled as hazardous waste

and sent to a RCRA approved waste facility. Processing, use or contamination of this product

may change the waste management options. State and local disposal regulations may differ

from federal disposal regulations. Dispose of container and unused contents in accordance

with federal, state and local requirements.

14. Transport Information

Domestic (Land, D.O.T.) -----------------------

Proper Shipping Name: SODIUM HYDROXIDE, SOLID

Hazard Class: 8

UN/NA: UN1823

Packing Group: II

Information reported for product/size: 300LB

International (Water, I.M.O.) -----------------------------

Proper Shipping Name: SODIUM HYDROXIDE, SOLID

Hazard Class: 8

UN/NA: UN1823

Packing Group: II

Information reported for product/size: 300LB

15. Regulatory Information

Carl Schroedl

# 000477237

46

--------\Chemical Inventory Status - Part 1\-----------------------------

----

Ingredient TSCA EC Japan

Australia

----------------------------------------------- ---- --- ----- ------

---

Sodium Hydroxide (1310-73-2) Yes Yes Yes Yes

--------\Chemical Inventory Status - Part 2\-----------------------------

----

--Canada--

Ingredient Korea DSL NDSL Phil.

----------------------------------------------- ----- --- ---- -----

Sodium Hydroxide (1310-73-2) Yes Yes No Yes

--------\Federal, State & International Regulations - Part 1\------------

----

-SARA 302- ------SARA 313--

----

Ingredient RQ TPQ List Chemical

Catg.

----------------------------------------- --- ----- ---- ----------

----

Sodium Hydroxide (1310-73-2) No No No No

--------\Federal, State & International Regulations - Part 2\------------

----

-RCRA- -TSCA-

Ingredient CERCLA 261.33 8(d)

----------------------------------------- ------ ------ ------

Sodium Hydroxide (1310-73-2) 1000 No No

Chemical Weapons Convention: No TSCA 12(b): No CDTA: No

SARA 311/312: Acute: Yes Chronic: No Fire: No Pressure: No

Reactivity: Yes (Pure / Solid)

Australian Hazchem Code: 2R

Poison Schedule: S6

WHMIS: This MSDS has been prepared according to the hazard criteria of the Controlled Products

Regulations (CPR) and the MSDS contains all of the information required by the CPR.

16. Other Information

NFPA Ratings: Health: 3 Flammability: 0 Reactivity: 1

Label Hazard Warning: POISON! DANGER! CORROSIVE. MAY BE FATAL IF SWALLOWED. HARMFUL IF

INHALED. CAUSES BURNS TO ANY AREA OF CONTACT. REACTS WITH WATER,

ACIDS AND OTHER MATERIALS.

Carl Schroedl

# 000477237

47

Label Precautions: Do not get in eyes, on skin, or on clothing.

Do not breathe dust.

Keep container closed.

Use only with adequate ventilation.

Wash thoroughly after handling.

Label First Aid: If swallowed, DO NOT INDUCE VOMITING. Give large quantities of water. Never give

anything by mouth to an unconscious person. In case of contact, immediately flush eyes or

skin with plenty of water for at least 15 minutes while removing contaminated clothing and

shoes. Wash clothing before reuse. If inhaled, remove to fresh air. If not breathing give

artificial respiration. If breathing is difficult, give oxygen. In all cases get medical attention

immediately.

Product Use: Laboratory Reagent.

Revision Information: No Changes.

Disclaimer: ***************************************************************************

*********************

Mallinckrodt Baker, Inc. provides the information contained herein in good faith but

makes no representation as to its comprehensiveness or accuracy. This document is

intended only as a guide to the appropriate precautionary handling of the material by a

properly trained person using this product. Individuals receiving the information must

exercise their independent judgment in determining its appropriateness for a particular

purpose. MALLINCKRODT BAKER, INC. MAKES NO REPRESENTATIONS OR

WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT

LIMITATION ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A

PARTICULAR PURPOSE WITH RESPECT TO THE INFORMATION SET FORTH

HEREIN OR THE PRODUCT TO WHICH THE INFORMATION REFERS.

ACCORDINGLY, MALLINCKRODT BAKER, INC. WILL NOT BE RESPONSIBLE

FOR DAMAGES RESULTING FROM USE OF OR RELIANCE UPON THIS

INFORMATION. ***************************************************************************

*********************

Prepared by: Environmental Health & Safety

Phone Number: (314) 654-1600 (U.S.A.)

Carl Schroedl

# 000477237

48

Appendix E: Further Research

The relation of gas product to concentration may take on the form of a logarithm of

the concentration minus an asymptotic (1 / (constant-concentration)) component. More

advanced mathematicians should try to describe the shape of this function, including the area

where conductivity approaches a small value related to the conductivity of solid sodium

hydroxide after the molarity of the solution becomes greater than sodium hydroxide’s

solubility. This region of the graph may be useful because electrolysis of sodium hydroxide

itself does produce hydrogen and oxygen gas as was discovered by Humphrey Davy in

1807(“Sodium: History”).

The scarcity of Kohlrausch coefficients nearly put an end to this experiment. Any

effort to find or publish Kohlrausch coefficients is encouraged. Numerous Kohlrausch

constants could also predict the results of a comparison of two electrolytes. These

coefficients could have determined whether it results could be attained for the original focus

of this experiment.

The original focus of this experiment was to determine which alkali hydroxide

electrolyte was more conductive at a variety of molarities. After extensive searching, no

dissociation constants for the alkali hydroxides could be found. The sources consulted

indicated that dissociation constants of alkali hydroxides would be similar and very large.

The virtually complete dissociation of these electrolytes would not have produced results

measurable with the instruments available. Those with more precise instruments could

potentially determine the constants.