Chemistry Finding the unknown concentration of the unknown solution?

Question

a 33.00 mL sample of an H2SO4 solution of unknown concentration is titrated with a 0.1222 M KOH solution A volume of 40.22 mL of KOH was required to reach the equivalence point.

 

What is the concentration of the unknown H2SO4 solution?

 

Please answer using four significant figures

Answer 1

This is a strong-acid strong-base titration. The general reaction is:

 

acid + base = salt + water

 

Therefore the balanced reaction is:

 

H₂SO₄ + 2KOH --> K₂SO₄ + 2H₂O

 

We see that 2 moles of KOH is required to neutralize 1 mole of H₂SO₄

 

40.22 mL KOH * 0.1222 mol/L * 1L/1000mL = 0.0049 moles of KOH

 

Using the mole-to-mole ratio of the reaction:

 

0.0049 mol KOH * 1 mol H₂SO₄/2 mol KOH= 0.00245 moles H₂SO₄ used in the reaction

 

Since we know that 33mL of H₂SO₄ was present originally, the concentration is just:

 

0.00245 mol H₂SO₄/33mL * 1000mL/L = 0.074 M H₂SO₄