Answer to Question #311843 in Chemistry for grey tyrant

Question

2. What is the concentration of an HNO3 solution if 25.0 ml reacts with 38.5 ml of 0.145 M K2PO4?

Answer 1

Solution:

Balanced chemical equation:

3HNO₃ + K₃PO₄ → 3KNO₃ + H₃PO₄

According to stoichiometry:

Moles of HNO₃ / 3 = Moles of K₃PO₄

or:

Molarity of HNO₃ × Volume of HNO₃ = 3 × Molarity of K₃PO₄ × Volume of K₃PO₄

Therefore,

Molarity of HNO₃ = 3 × Molarity of K₃PO₄ × Volume of K₃PO₄ / Volume of HNO₃

Molarity of HNO₃ = (3 × 0.145 M × 38.5 mL) / (25.0 mL) = 0.6699 M ≈ 0.670 M

Molarity of HNO₃ = 0.670 M

Answer: The concentration of an HNO₃ solution is 0.670 M