Answer to Question #111843 in Chemistry for hello

Question

When a chemist titrates a standard solution of 308.25 mL of nitric acid (HNO3) with 0.155 M potassium hydroxide (KOH) , she finds that it requires 246.6 mL of the base to reach the endpoint of the titration. What is the molarity of the acid solution ?

Answer 1

Solution:

The balanced chemical equation for the reaction between HNO₃ and KOH:

HNO₃ + KOH = KNO₃ + H₂O

At the endpoint of the titration: n(HNO₃) = n(KOH)

C(HNO₃) × V(HNO₃) = C(KOH) × V(KOH);

C(HNO₃) × 308.25 mL = (0.155 M × 246.6 mL);

C(HNO₃) = (0.155 M × 246.6 mL) / (308.25 mL) = 0.124 M

Molarity of HNO₃ = C(HNO₃) = 0.124 M.

Answer: 0.124 M is the molarity of the acid solution (HNO₃).