Question

50.0 mL of a 0.45 mol/L sulfuric acid solution reacted completely with 68.0 mL of potassium hydroxide solution. What is the concentration of potassium hydroxide?

Answer 1

first write the balanced equation

H2SO4 + 2KOH ---> 2K2SO4 + H2O

from this equation t is clear that one mole of H2SO4 required 2 moles of KOH to react completely

now calculate the no of moles of H2SO4

no of moles of H2SO4 = molarity of H2SO4 x volume of H2SO4 in liters

= 0.45 mol/L x 0.05 L

= 0.0225 moles

so

0.0225 moles required 2 x 0.0225 moles = 0.045 moles of KOH

now we have volue of KOH and moles of KOH

Molarity of KOH = moles of KOH / volume of KOH in liters

M = 0.045 mol / 0.068 L

= 0.662 M