What is the initial concentration of chloric acid?

Question

A 25.00 mL sample of of a chloric acid solution is completely neutralized using 22.44 mL of 0.157 M potassium hydroxide. 

Answer 1

The reaction taking place is ...

HClO₃ + KOH ==> H₂O + KClO₃ ... balanced equation

First, find moles of KOH used to neutralize the HClO₃

22.44 ml x 1 L / 1000 ml x 0.157 mol/L = 0.00352 mols KOH

Next, find mols of HClO₃ present:

0.00352 mols KOH x 1 mol HClO₃ / mol KOH = 0.00352 mols HClO₃ present

Next, correct for the volume to express this in moles/liter (M):

25.00 ml x 1 L / 1000 ml = 0.025 L

0.00352 mols / 0.025 L = 0.141 M (initial concentration of HClO_3)