Acid Base TitrationsLesson 4

In a titration the molarity of one chemical is determined by reacting it with another one with known molarity (standard).

Erlenmeyer Flask

Burette

Pipette

Special Equipment is used for a titration

Magnetic Stirrer

Pipette Filler

Volumetric Flask

Digital Balance

Solid acid to make a standard solution

Titration Calculation

1. 6.50 mL of 0.100 M H2C2O4 is required to neutralize 10.0 mL of KOH solution in a titration. Calculate the base concentration.

H2C2O4 + 2KOH K2C2O4 + 2H2O0.00650 L 0.0100 L0.100 M ? M

= 0.130 M

0.0100 L

x 2 mole KOH 1 mole H2C2O4

x 0.100 mole 1 L

0.00650 L H2C2O4

[KOH] =

If you get data in a table, you need to subtract the final burette reading from the initial to get the volume of acid or base added.

If you have multiple trials, average them but reject any volumes that are way off. Use some common sense.

Burette Volume in mL

Initial 0.00 mL 8.95 mL 17.41 mLFinal 8.95 mL 17.41mL 25.85 mLVolume Added 8.95 mL 8.46 mL 8.44 mL

reject

average 8.46 + 8.44 = 8.45 mL 2

Now it's your turn to try one!

Titration Calculation

2. 8.95 mL , 8.46 mL and 8.44 mL of 0.200 M H2SO4 was required to neutralize 25.0 mL of KOH solution in a titration. Calculate the base concentration.

H2SO4 + 2KOH K2SO4 + 2H2O0.00845 L 0.0250 L0.200 M ? M

[KOH] = 0.00845 L H2SO4 x 0.200 mole x 2 mole KOH 1 L 1 mole H2SO4

0.0250 L

= 0.135 M

3. Calculate the mass of H2C2O4.2H2O required to make 100.0 mL of a

0.1000 M standard solution to use in your titration lab tomorrow.

0.100 L x 0.1000 mol x 126.06 g = 1.261 g1 L 1 mole