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Decomposition of Hydrogen Peroxide
INTRODUCTION
The branch of physical chemistry which deals with the rate of
reactions in called chemical kinetics.
The study of chemical kinetics includes:
The rate of the reactions and rate laws
The factors are temperature, pressure concentration and catalyst that
influence the rate of a reaction.
The mechanism or the sequence of steps by which a reaction occurs.
The knowledge of the rate of reactions in very valuable to understand
the chemical of reactions.
It is also great importance in selecting optimum conditions for an
industrial process so that it proceeds at a rate to give maximum yield.
The rate of reactions is defined as change in concentration of any of
reactant or products per unit time.
Eg: Consider a simple reaction
A B
The concentration of the reactant a decrease and that of B increases as
time passes.
rate=−d [ A ]
dt
rate =+ d [ B ]dt
Where [ ] represents the concentration in mole per liter
Sahyadri Science College (Autonomous), Shimoga 1
Decomposition of Hydrogen Peroxide
dt = Infinitesimally small change in concentration
The units of reactions rates expressed in moles per liter
Factors influencing the reaction rate
The rate of chemical reaction is not a fixed quantity and varies with
the experimental conditions.
Rate of reactions influences by the following factors.
i. Nature of reactants
ii. Concentration of the reactant
iii. Temperature
iv. Presence of catalyst
v. Surface area of the catalyst or reactant
vi. Radiations or presence of light
Rate Law and Rate Constant
The rate of reaction is directly proportional to the reactant
concentration each concentration being raised to some power.
Thus, Rate α [A]n
Rate = K [A]n
For reaction
2A+B Products
The rate reaction expressed
Rate = K [A]n [B]n
An expression which shows how the reaction rate is related to
concentration is need the rate law are rate equations.
Sahyadri Science College (Autonomous), Shimoga 2
Decomposition of Hydrogen Peroxide
Reaction
2N2O5 4NO2+O2
Rate = K [N2O5]2
H2+I2 2HI
Rate = K [H2] [I2]
Order of reaction
The order of reaction is defined as the of the sum of the power of
concentration in the rate law
Rate = K[A]m [B]n
Order of reaction in ( m + n)
Rate = K [N2O5]2
Rate = K [H2][I2]
Rate = K [NO2]2
m+n = 1, it is first order reaction
m+n = 2, it is second order reaction
m+n = 3, it is third order reaction
First Oder reaction
A reaction is said to be first order if the rate is given by the expression
of the type.
R = K1CA
Sahyadri Science College (Autonomous), Shimoga 3
Decomposition of Hydrogen Peroxide
Best example for the first order reaction in decomposition of hydrogen
peroxide.
Hydrogen peroxide always campore exothermically into water and
oxygen gas spontaneously.
2H2O2 2H2O + O2 ↑
The liberation of oxygen and energy in decomposition has dangerous
side effect splitting high concentration of hydrogen peroxide on a flammable
substance can cause immediate.
The rate of decomposition in dependent on the temperate and
concentration of the hydrogen peroxide as well as the pH, presence of
impurities and stabilities.
The decomposition occurs more rapidly in alkali so acid is of then
added as stabilizer.
Sahyadri Science College (Autonomous), Shimoga 4
Decomposition of Hydrogen Peroxide
ABOUT HYDROGEN PEROXIDE
Hydrogen peroxide
IUPAC name Hydrogen peroxide
Other names µ-1KO, 2KO’ – Dioxidodihydrogen
Dihydrogen dioxide
Hydrogen dioxide
Dioxidane
Properties
Molecular formula H2O2
Molar mass 34.0147 g/mol
Appearance Very light blue color; colorless in solution
Density 1.463 g/cm3
Melting point -0.43 °C, 273 K, 31 °F
Boiling point 150.2 °C, 423 K, 302 °F
Solubility in water Miscible
Acidity (p Ka) 11.62
Viscosity 1.245 cP (20 °C)
Dipole moment 2.26 D
Sahyadri Science College (Autonomous), Shimoga 5
Decomposition of Hydrogen Peroxide
Hydrogen peroxide (H2O2) is a very pale liquid which appears
colourless in a dilute solution, slightly more viscous than water. It is a weak
acid. It has strong oxidizing properties and is therefore a powerful bleaching
agent that is mostly used for bleaching paper, but has also found use as a
disinfectant, as an oxidizer, as an antiseptic, and in rocketry ( particularly in
high concentrations as high –test peroxide or HTP) as a monopropellant, and
in bipropellant systems. The oxidizing capacity of hydrogen peroxide is so
strong that the chemical is considered a highly reactive oxygen species.
Hydrogen peroxide is naturally produced as a by-product of oxygen
metabolism, and virtually all organisms possess enzymes known as
peroxidases, which harmlessly and catalytically decompose low
concentrations of hydrogen peroxide to water and oxygen.
History
Hydrogen peroxide was first isolated in 1818 by Louis Jacques
Thénard by reacting barium peroxide with nitric acid. An improved version
of this process used hydrochloric acid, followed by sulfuric acid to
precipitate the barium sulfate byproduct. Thénard's process was used from
the end of the 19th century until the middle of the 20th century. Modern
production methods are discussed below.
For a long time, pure hydrogen peroxide was believed to be unstable,
because attempts to separate the hydrogen peroxide from the water, which is
present during synthesis, failed. This was because traces of solids and heavy
metal ions led to a catalytic decomposition or explosions of the hydrogen
peroxide. 100 % pure hydrogen peroxide was first orbited through vacuum
distillation by Richard Wolffenstein in 1894. At the end of 19th century,
Sahyadri Science College (Autonomous), Shimoga 6
Decomposition of Hydrogen Peroxide
Petre Melikishvili and his pupil L. Pizarjevski showed that of the many
proposed formulas of hydrogen peroxide, the correct one was H-O-O-H.
Storage
Regulations vary, but low concentrations, such as 3%, are widely
available and legal to buy for medical use. Higher concentrations may be
considered hazardous and are typically accompanied by a material safety
data sheet(MSDS). In high concentrations, hydrogen peroxide is an
aggressive oxidizer and will corrode many materials, including human skin.
In the presence of a reducing agent, high concentrations of H2O2 will react
violently.
Hydrogen peroxide should be in a cool, dry, well –ventilated area and
away from any flammable or combustible substances. It should be stored in a
container composed of non reactive materials such as stainless steel or glass
( other materials including some plastics and aluminum alloys may also be
suitable). Because it breaks down quickly when exposed to light, it should be
stored in an opaque container, and pharmaceutical formulations typically
come in brown bottles that filer out light.
Physical Properties
H2O2 adopts a nonplanar structure of C2 symmetry. Although chiral,
the molecule undergoes rapid racemization. The flat shape of the anti
Sahyadri Science College (Autonomous), Shimoga 7
Decomposition of Hydrogen Peroxide
conformer would minimize steric repulsions, the 90° torsion angle of the syn
conformer would optimize mixing between the filled p-type orbital of the
oxygen (one of the lone pairs) and the LUMO of the vicinal O-H bond.[3] The
observed anticlinal "skewed" shape is a compromise between the two
conformers.
While the anti conformer would minimize steric repulsions, a 90°
torsion angle would optimize mixing between the filled p-type orbital of the
oxygen (one of the lone pairs) and the LUMO of the vicinal O-H bond.[8]
Reflecting a compromise between the two interactions, gaseous and liquid
hydrogen peroxide adopts an anticlinal "skewed" shape. This rotational
conformation is a compromise between the anti conformer, which would
minimize steric repulsion, and between the syn conformer that associates
0¬H bonds with lone pairs on the oxygen atoms. Despite the fact that the 0-0
bond is a single bond, the molecule has a remarkably high barrier to
complete rotation of 29.45 kllmol (compared with12.5 kllmol for the
rotational barrier of ethane). The increased barrier is also attributed to
repulsion between one lone pair and other lone pairs. The bond angles are
affected by hydrogen bonding, which is relevant to the structural difference
between gaseous and crystalline forms; indeed a wide range of values is seen
in crystals containing molecular H2O2.
Chemical properties
H2O2is one of the most powerful oxidizers known stronger than
chlorine, chlorine dioxide and potassium permanganate. Also, through
catalysis, H2O2 can be converted into hydroxyl radicals (.OH) with reactivity
second only to fluorine.
Sahyadri Science College (Autonomous), Shimoga 8
Decomposition of Hydrogen Peroxide
Oxidant Oxidation potential, V
Fluorine 3.0
Hydroxyl radical 2.8
Ozone 2.1
Hydrogen peroxide 1.8
Potassium permanganate 1.7
Chlorine dioxide 1.5
Chlorine 1.4
Hydrogen peroxide can decompose spontaneously into water and
oxygen. It usually acts as an oxidizing agent, but there are many reactions
where it acts as a reducing agent, releasing oxygen as a by-product. It also
readily forms both inorganic and organic peroxides.
Decomposition
Hydrogen peroxide always decomposes (disproportionates)
exothermically into water and oxygen gas spontaneously:
2H2O2 2H2O + O2
This process is very favorable thermodynamically. It has a H0 of
98.2 kJ mol-1 and a G0 -119.2 kJ mol-1 and a S of 70.5 J mol -1 per K-1
The rate of decomposition is dependent on the temperature and
concentration of the peroxide, as well as the pH and the presence of
impurities and stabilizers. Hydrogen peroxide is incompatible with many
substances that catalyse its decomposition, including most of the Transition
metals and their compounds. Common catalysts include manganese dioxide,
and silver. The same reaction is catalysed by the enzyme catalase, found in
the liver, whose main function in the body is the removal of toxic byproducts
Sahyadri Science College (Autonomous), Shimoga 9
Decomposition of Hydrogen Peroxide
of metabolism and the reduction of oxidative stress. The decomposition
occurs more rapidly in alkali, so acid is often added as a stabilizer.
The liberation of oxygen and energy in the decomposition has
dangerous side effects. Spilling high concentrations of hydrogen peroxide on
a flammable substance can cause an immediate fire, which is further fueled
by the oxygen released by the decomposing hydrogen peroxide. High-
strength peroxide (also called high-test peroxide, or HTP) must be stored in a
suitable vented container to prevent the buildup of oxygen gas, which would
otherwise lead to the eventual rupture of the container. In the presence of
certain catalysts, such as Fe2+ or Ti3+, the decomposition may take a different
path, with free radicals such as HO' (hydroxyl) and HOO' being formed. A
combination of H2O2 and Fe2+ is known as Fenton's reagent.
A common concentration for hydrogen peroxide is "20 volume",
which means that when 1 volume of hydrogen peroxide is decomposed, it
produces 20 volumes of oxygen. A 20 "volume" concentration of hydrogen
peroxide is equivalent to 1.67 mol/dm3 (Molar solution) or about
6%.Hydrogen peroxide available at drug stores is three percent solution. In
such small concentrations, it is less stable, and decomposes faster. It is
usually stabilized with acetanilide, a substance which has toxic side effects
in significant amounts.
Redox reactions
In aqueous solution, hydrogen peroxide can oxidize or reduce a
variety of inorganic ions. When it acts as a reducing agent, oxygen gas is
also produced. In acidic solutions Fe2+ is oxidized to Fe3+,
2Fe2+(aq) +H2O2 + 2H+(aq) 2Fe+3 (aq) +2H2O (l)
Sahyadri Science College (Autonomous), Shimoga 10
Decomposition of Hydrogen Peroxide
and sulphite (SO32-) is oxidized to sulphate (SO4
2-). However, potassium
permanganate is reduced to Mn2+ by acidic H2O2. Under alkaline conditions,
however, some of these reactions reverse; for example, Mn2+ is oxidized to
Mn4+ (as MnO2).
Another example of hydrogen peroxide acting as a reducing agent is
the reaction with sodium hypochlorite, which is a convenient method for
preparing oxygen in the laboratory.
NaOCl + H2O2 O2 + NaCl + H2O
Hydrogen peroxide is frequently used as an oxidizing agent in organic
chemistry. One application is for the oxidation of thioethers to sulfoxides.
For example, methyl phenyl sulfide was oxidized to methyl phenyl sulfoxide
in 99% yield in methanol in 18 hours (or 20 minutes using a TiCh catalyst).
Ph-S-CH3 + H2O2 Ph-S(O)-CH3 + H2O
Preparation of Oxalic acid solution
Weigh accurately 0.315g of oxalic acid into a clean 100ml volumetric
flask and dissolve the crystals. Dilute the crystals up to the mark with
distilled water. Mix the solution for uniform concentration.
Weight of oxalic acid = 0.315g
0.315 x 10 Normality of oxalic acid = --------------------- = 0.05 N
63 Preparation of potassium permanganate solution
Weigh accurately 0.790g of potassium permanganate crystals into
clean 500ml beaker and dissolve the crystals. Dilute the solution up to the
mark with distilled water. Mix the solution for uniform concentration.
Sahyadri Science College (Autonomous), Shimoga 11
Decomposition of Hydrogen Peroxide
Standardization of potassium permanganate
Pipette out 10 ml of standard 0.05 N oxalic acid and 1 test tube 2 N
sulphuric acid solutions into a clean 250ml conical flask. Heat the solution
and titrate it with KMnO4 till the color changes from colorless to pale pink.
Note down the titrate value and continue the titration for agreeing values.
Tabular column:
Burette - KMnO4 solution
Conical flask - 10ml oxalic acid + 1 test tube 2N H2SO4
Indicator - Self indicator
End point - Colorless to pale pink color
Burette readings in ml Trial I Trial 2
Final burette reading 10.2 10.2
Initial burette reading 0.0 0.0
Volume of KMnO4 consumed 10.2 10.2
V = 10.2 ml
(NV)KMnO4 = (NV) oxalic acid
(N x V) Oxalic acid (V)KMnO4 = ----------------------------
(V) KMnO4
0.05 x 10 = ----------------------------
10.2
= 0.049 N
Sahyadri Science College (Autonomous), Shimoga 12
Decomposition of Hydrogen Peroxide
Preparation of hydrogen peroxide solution
Take 5 ml of 30 % H2O2 in a clean measuring jar and pour it into a
beaker containing 500 ml of distilled water. Mix thoroughly for uniform
concentration.
Standardization of Hydrogen Peroxide
Pipette out 10 ml of prepared H2O2 solution into a clean 250 ml
conical flask and add 1 test tube 2 N sulphuric acid solution and titrate it
with standard KMnO4 till the color changes from colorless to pale pink. Note
down the titrate value and continue the titration for agreeing values.
Tabular column:
Burette - Standard KMnO4 solution
Conical flask- 10ml H2O2 + 1 test tube 2N H2SO4
Indicator - self indicator
End point - colorless to pale pink color
Burette readings in ml Trial 1 Trial 2Final burette reading 30.1 30.1
Initial burette reading 0.0 0.0
Vol. of KMnO4 consumed 30.1 30.1
V=30.1 ml
(NV) H2O2 = (NV) KMnO4
(NV) KMnO4
(NxV) H2O2 = --------------------------
(V) H2O2
0.049 x 30.1= ------------------------- 10= 0.147 N
STUDIES OF KINETICS
Sahyadri Science College (Autonomous), Shimoga 13
Decomposition of Hydrogen Peroxide
Take 50 ml of 0.147 N standard H2O2 in two separate reagent bottles.
Maintain the temperature of one reagent bottle at room temperature (28oC)
and another at 35°C. Add 3 ml of 3% catalyst to both the reagent bottles.
Start the stop watch, when half of the volume of catalyst solution has been
poured into the reagent bottles. This is taken as zero time. Mix the contents
in each reagent bottles thoroughly and immediately pipette out 10ml of
reaction mixture into a conical flask containing ice cold water and one test
tube 2N H2SO4. The solution is titrated against O.05N standard KMnO4
Solution. Note down the end point by color change. Let the titer value at zero
time be Vo Repeat the same procedure at the interval of 5 minutes. Let the
titer value at any time be Vt. The Vt values decreases as the concentration of
H2O2 in the reaction mixture gradually falls. The calculated value of K can
be obtained by using the formula,
K=2 .303×log
V o
V t
t /s
Plot the graph log Vo/Vt versus time, a straight line is obtained which
pass through the origin. Slope of the line gives values of rate constant (K).
Theoretical value of k is compared with graphical value of K.
We know that the rate constant k is related to the activation energy
(Ea).Thus, by measuring the rate constant (k) at two different temperatures,
we can evaluate activation energy (Ea).
Ea= logK2
K1×2.303×R×( T1×T 2
T 2 −T1) KJ /mol
Similarly the above procedure is carried out by adding 5 ml catalyst to
95 ml H2O2 solution at two different temperatures.
Sahyadri Science College (Autonomous), Shimoga 14
Decomposition of Hydrogen Peroxide
The above procedure is followed for these catalysts,
a) Ferric chloride
b) Cupric chloride
c) Stannous chloride
d) Cobalt chloride
e) Zinc Chloride
f) Nickel Chloride
g) Potassium Iodide
h) Mixture of mohr salt of Fe2+ and Fe3+
i) Ferric ammonium sulphate
Catalytic Variation
Catalysis is the change in rate of a chemical reaction due to the
participation of a substance called a catalyst. Unlike other reagents that
participate in the chemical reaction, a catalyst is not consumed by the
reaction itself. A catalyst may participate in multiple chemical
transformations. Catalysts that speed the reaction are called positive
catalysts. Substances that interact with catalysts to slow the reaction are
called inhibitors (or negative catalysts). Substances that increase the activity
of catalysts are called promoters, and substances that deactivate catalysts are
called catalytic poisons.
Kinetically, catalytic reactions are typical chemical reactions, i.e. the
reaction rate depends on the frequency of contact of the reactants in the rate-
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Decomposition of Hydrogen Peroxide
determining step. Usually, the catalyst participates in this slow step, and
rates are limited by amount of catalyst and its "activity". In heterogeneous
catalysis, the diffusion of reagents to the surface and diffusion of products
from the surface can be rate determining. Analogous events associated with
substrate binding and product dissociation apply to homogeneous catalysts.
Sahyadri Science College (Autonomous), Shimoga 16
Decomposition of Hydrogen Peroxide
A) POTASSIUM IODIDE
1. Reaction mixture = 1 ml (0.09g) Potassium Iodide + 50 H2O2 + 49 g
H2O correspondingly for 2 and 3 ml the volume of water changed. i.e. 48 and
47 ml respectively and those are tabulated below.
Table 1:
Catalyst: Potassium Iodide (KI)
Temperature: 28oC
Concentration: 1 ml
Vo : 19.5ml
Time in
minutes
Vt in
mllog (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 0
5 18.4 0.0252 0.0116
10 18.3 0.0275 0.0063
15 18.2 0.0299 0.0043
20 18.0 0.0348 0.0040
25 17.4 0.0519 0.0047
30 17.0 0.0595 0.0045
35 16.8 0.0647 0.0042
40 16.5 0.0725 0.00417
45 16.0 0.0859 0.0043
Sahyadri Science College (Autonomous), Shimoga 17
Decomposition of Hydrogen Peroxide
Table 2:
Catalyst : Potassium Iodine (KI)
Temperature: 28oC
Concentration: 2 ml
Vo: 19.5ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 19.5 0 05 19.0 0.0112 0.005110 18.1 0.032 0.007415 17.4 0.049 0.007520 16.7 0.067 0.007525 16.3 0.077 0.007130 15.5 0.199 0.007635 14.8 0.11 0.007840 14.4 0.13 0.007545 13.9 0.014 0.0075
Table 3:
Catalyst: Potassium Iodine (KI)
Temperature: 28oC
Concentration: 3 ml
Vo : 19.3ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 Vo=19.3 0 05 18.1 0.027 0.012810 17.9 0.032 0.007515 17.3 0.047 0.007220 16.3 0.073 0.008425 15.5 0.095 0.008730 15.0 0.10 0.008435 14.5 0.12 0.008140 13.6 0.15 0.008545 13.3 0.16 0.0082
Sahyadri Science College (Autonomous), Shimoga 18
Decomposition of Hydrogen Peroxide
B) NICKEL CHLORIDE
1. Reaction mixture = 1 ml (0.09g) Nickel chloride + 50 H2O2 + 49 g
H2O correspondingly for 2 and 3 ml the volume of water changed. i.e. 48 and
47 ml respectively and those are tabulated below.
Table 4 :
Catalyst : NiCl2
Temperature: 28oC
Concentration : 1 ml
Vo : 18.5 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 18.8 0 010 18.5 0.0069 0.001615 18.3 0.0117 0.001720 18.0 0.0188 0.002125 18.2 0.014 0.001230 18.1 0.016 0.001235 17.9 0.021 0.001440 17.8 0.023 0.001345 17.5 0.031 0.0015
Sahyadri Science College (Autonomous), Shimoga 19
Decomposition of Hydrogen Peroxide
Table 5 :
Catalyst : NiCl2
Temperature: 28oC
Concentration : 2 ml
Vo : 18.5 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 18.3 0.0047 0.002110 18.2 0.071 0.001615 17.8 0.016 0.002520 18.3 0.0047 0.005425 17.7 0.019 0.001730 17.5 0.024 0.001835 17.4 0.026 0.001740 17.4 0.026 0.001545 17.4 0.026 0.0013
Table 6 :
Catalyst : NiCl2
Temperature: 26oC
Concentration : 3 ml
Vo : 18.5 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog( V o
V t)
0 0 0 05 17.9 0.014 0.0065910 17.4 0.026 0.0061315 17.2 0.031 0.004820 17.1 0.034 0.003925 16.9 0.039 0.003630 16.8 0.041 0.003235 16.5 0.049 0.003240 16.1 0.060 0.003445 15.8 0.068 0.0035
Sahyadri Science College (Autonomous), Shimoga 20
Decomposition of Hydrogen Peroxide
C) FERRIC CHLORIDE
1. Reaction mixture = 1 ml (0.09g) ferric chloride + 50 H2O2 + 49 g
H2O correspondingly for 2 and 3 ml the volume of water changed. i.e. 48 and
47 ml respectively and those are tabulated below.
Table 6 :
Catalyst : FeCl3
Temperature: 27oC
Concentration : 1 ml
Vo : 19 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
Unit 0 0 0 05 15.6 0.085 0.0310 15.0 0.102 0.02315 14.3 0.123 0.01820 13.1 0.161 0.01825 12.7 0.161 0.014830 11.8 0.174 0.013435 11.4 0.20 0.013640 11.0 0.23 0.013645 9.5 0.30 0.0154
Sahyadri Science College (Autonomous), Shimoga 21
Decomposition of Hydrogen Peroxide
Table 7 :
Catalyst : FeCl3
Temperature: 27oC
Concentration : 2 ml
Vo : 16.8ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 15.5 0.03 0.016110 14.1 0.076 0.017515 12.7 0.12 0.018620 11.6 0.16 0.018525 10.3 0.212 0.019530 9.6 0.243 0.018635 8.6 0.290 0.019140 7.9 0.327 0.018845 7.5 0.3502 0.0179
Table 8 :
Catalyst : FeCl3
Temperature: 27oC
Concentration : 3 ml
Vo : 16.5 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 15.4 0.029 0.0138010 13.6 0.083 0.019315 11.5 0.196 0.030020 9.0 0.26 0.030325 7.5 0.342 0.031530 6.4 0.411 0.031535 5.5 0.477 0.031340 4.7 0.545 0.031445 4.2 0.594 0.03042
Sahyadri Science College (Autonomous), Shimoga 22
Decomposition of Hydrogen Peroxide
D) COPPER CHLORIDE
1. Reaction mixture = 1 ml (0.09g) copper chloride + 50 H2O2 + 49 g
H2O correspondingly for 2 and 3 ml the volume of water changed. i.e. 48 and
47 ml respectively and those are tabulated below.
Table 9 :
Catalyst : CuCl2
Temperature: 27oC
Concentration : 0.3 ml
Vo : 17.5 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog( V o
V t)
0 0 0 05 17.2 0.075 0.003410 16.8 0.017 0.004015 16.2 0.033 0.005720 15.9 0.044 0.005125 15.3 0.058 0.005330 14.8 0.072 0.005535 14.5 0.081 0.005140 14.0 0.096 0.005545 13.9 0.10 0.0051
Sahyadri Science College (Autonomous), Shimoga 23
Decomposition of Hydrogen Peroxide
Table 10 :
Catalyst : CuCl2
Temperature: 27oC
Concentration : 0.5 ml
Vo : 17.2 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 16.2 0.026 0.011910 15.0 0.059 0.01315 14.8 0.065 0.01020 14.7 0.068 0.007825 14.5 0.075 0.006830 14.1 0.086 0.006635 13.7 0.098 0.006540 13.5 0.105 0.006045 13.0 0.121 0.0062
Table 11 :
Catalyst : CuCl2
Temperature: 27oC
Concentration : 1 ml
Vo : 17.0 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 16.0 0.026 0.01210 15.5 0.040 0.009215 15.0 0.054 0.0083420 14.8 0.060 0.006925 14.3 0.075 0.006930 13.8 0.090 0.006935 13.6 0.096 0.006340 12.9 0.11 0.006945 12.6 0.13 0.0066
Sahyadri Science College (Autonomous), Shimoga 24
Decomposition of Hydrogen Peroxide
e) MIXTURE Of Fe+2and Fe+3 AMMONIUM SULPHATE
1. Reaction mixture = 1 ml (0.09g) Mixture of Fe+2and Fe+3
Ammonium sulphate + 50 H2O2 + 49 g H2O correspondingly for 2 and 3 ml
the volume of water changed. i.e. 48 and 47 ml respectively and those are
tabulated below.
Table 13 :
Catalyst : Mixture of Fe+2and Fe+3 Ammonium sulphate
Temperature: 27oC
Concentration : 2 ml
Vo : 16.4 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 Vo=19.3 0 05 16.3 0.0026 0.0012210 15.0 0.038 0.008915 14.4 0.056 0.008620 13.9 0.075 0.008225 13.2 0.094 0.0086830 12.8 0.107 0.0082635 12.3 0.124 0.0082240 11.8 0.142 0.0082345
Sahyadri Science College (Autonomous), Shimoga 25
Decomposition of Hydrogen Peroxide
Table 14 :
Catalyst : Mixture of Fe+2and Fe+3 Ammonium sulphate
Temperature: 27oC
Concentration : 3 ml
Vo : 16.1 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 14.6 0.042 0.019510 12.9 0.096 0.02215 11.5 0.146 0.02220 10.1 0.20 0.02325 9.1 0.24 0.02230 8.5 0.27 0.021235 7.0 0.36 0.02340 6.2 0.414 0.02345 5.3 0.482 0.022
Table 15 :
Catalyst : Mixture of Fe+2and Fe+3 Ammonium sulphate
Temperature: 27oC
Concentration : 4 ml
Vo : 16.0 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 0 0 05 14.6 0.039 0.018210 13.4 0.077 0.017715 11.1 0.158 0.02420 9.6 0.22 0.02525 8.1 0.295 0.02730 7.1 0.35 0.02735 6.2 0.41 0.02740 5.4 0.47 0.02745
Sahyadri Science College (Autonomous), Shimoga 26
Decomposition of Hydrogen Peroxide
TEMPERATURE VARIATION
Temperature is a physical property of matter that quantitatively
expresses the common notions of hot and cold.
Temperature relates to the thermal energy held by an object or a
sample of matter, which is the kinetic energy of the random motion of the
particle constituents of matter. While the thermal energy of an object is
proportional to the amount of matter it contains, temperature measures
thermal energy in a manner that is independent of size; it is an intensive
property, while thermal energy is an extensive property.
Temperature is one of the principal properties studied in the field of
thermodynamics. The empirical definition of temperature arises from the
conditions of thermodynamic equilibrium,
On the molecular level, temperature is the result of the motion of the
particles that constitute the material. Moving particles carry kinetic energy.
Temperature increases as this motion and the kinetic energy increase. The
motion may be the translational motion of particles, or the energy of the
particle due to molecular vibration or the excitation of an electron energy
level.
Similarly the above procedure is carried out by adding 2 ml catalyst
to correspondingly varying water with 50 ml of H2O2 solution at different
temperature
Sahyadri Science College (Autonomous), Shimoga 27
Decomposition of Hydrogen Peroxide
Table 16 : KI
Temperature: 32oC
Concentration : 2 ml
Vo : 32 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog( V o
V t)
0 Vo= 32 0 05 29.3 0.0175 0.038210 28.0 0.0133 0.057915 27.4 0.0103 0.067320 25.5 0.0113 0.098625 25.0 0.0098 0.107230 24.0 0.0095 0.124935 22.8 0.0096 0.147240 21.6 0.0098 0.170645 21.0 0.0093 0.1829
Table 17 : NiCl2
Temperature: 32oC
Concentration : 2 ml
Vo : 25.7 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog ( V o
V t)
0 25.7 0 05 15.2 0.02280 0.105010 6.5 0.05970 0.137415 3.0 0.093281 0.143220 1.6 1.2058 0.138825 1.2 1.330 0.122530 1.0 1.4099 0.108235 0.9 1.3944 0.0914045
Sahyadri Science College (Autonomous), Shimoga 28
Decomposition of Hydrogen Peroxide
Table 18 : FeCl3
Temperature: 32oC
Concentration : 2 ml
Vo : 28.8 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog( V o
V t)
0 28.8 0 05 25.8 0.021 0.047710 23.8 0.0019 0.082815 21.7 0.018 0.122920 20.8 0.016 0.141325 19.0 0.016 0.180630 18.0 0.015 0.20435 16.8 0.015 0.23440 15.3 0.014 0.27445
Table 20 : Fe2+ & Fe3+ Mixture
Temperature: 32oC
Concentration : 3 ml
Vo : 8.0 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog( V o
V t)
0 8 0 05 7.6 0.0222 0.10210 6.6 0.0835 0.019215 6.3 0.1037 0.015920 5.8 0.1396 0.016025 5.4 0.1706 0.015730 4.8 0.221 0.016935 4.7 0.230 0.015140 4.5 0.249 0.0143
Sahyadri Science College (Autonomous), Shimoga 29
Decomposition of Hydrogen Peroxide
Table 21 : CuCl2
Temperature: 32oC
Concentration : 0.3 ml
Vo : 8 ml
Time in minutes
Vt in ml log (V o
V t) K=2 .303
tlog( V o
V t)
0 38.8 0 05 37.7 0.0124 0.0057110 37 0.020 0.004615 36.2 0.030 0.004120 35.7 0.036 0.004125 35.3 0.041 0.003730 34.7 0.048 0.003635 33.7 0.061 0.004040 33 0.070 0.040
Sahyadri Science College (Autonomous), Shimoga 30
Decomposition of Hydrogen Peroxide
RESULTS AND DISCUSSION
Catalyst Conc. in ml
T1 T2 K1 K2 Ea
FeCl3 2 ml /2ml 27oC 32oC 4.606 3.45 43.77x103
KI 2 ml /2ml 28oC 32oC 3.822 2.118 112.5x103
CuCl2 0.3 ml /0.3 ml
26oC 32oC 3.454 1.888 76.88x103
NiCl2 2 ml /2ml 28oC 32oC 2.39512 3.4545 69.88x103
Mixture of Fe2+ & Fe3+
3 ml /3ml 27oC 32oC 3.4545 3.9381 19.93x103
Sahyadri Science College (Autonomous), Shimoga 31
Decomposition of Hydrogen Peroxide
CONCLUSION
1. Rate of decomposition of H2O2 is directly proportional concentration
of the catalyst.
R Concentration of the Catalyst
i.e. the rate constant increases as the concentration of catalyst
(FeCl3, CuCl2, KI, mixture of Fe2+ and Fe3+, NiCl2) increases as shown
in the above tables 1 – 15.
2. Rate of decomposition of H2O2 is directly proportional concentration
of the temperature of the reaction media.
R temperature of the Catalyst
i.e. the rate constant increases as the temperature of catalyst
(FeCl3, CuCl2, KI, mixture of Fe2+ and Fe3+, NiCl2) increases as shown
in the above tables 16 – 21.
3. Rate of decomposition of H2O2 is independent on the concentration of
following catalyst.
( SnCl2, ZnCl2, CoCl2, Ferric ammonium sulphate)
Sahyadri Science College (Autonomous), Shimoga 32
Decomposition of Hydrogen Peroxide
BIBLIOGRAPHY
1. C.W. Jones, J.H. Clark, Application of Hydrogen peroxide and
Derivatives. Royal Society of Chemistry, 1999.
2. Hydrogen Peroxide MSDS
3. Ozone Lab Peroxide Compatibility
4. Principles of Physical Chemistry by Puri, Sharma, Kalia
5. www.wikipedia.org
Sahyadri Science College (Autonomous), Shimoga 33
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