Question

The solubility product of AgCl is 1.8 × 10^–10. Precipitation of AgCl will occur only when equal volumes of which of the following solutions are mixed ?

• A. 10^–4 M Ag⁺ and 10^–4 M Cl^–
• B. 10^–7 M Ag⁺ and 10^–7 M Cl^–
• C. 10^–5 M Ag⁺ and 10^–5 M Cl^–
• D. 10^–10 M Ag⁺ and 10^–10 M Cl^–

Answer 1

Answer: (A)

10^–4 M Ag⁺ and 10^–4 M Cl^–

Answer 2

After mixing,

[Ag⁺] = $\frac{1}{2}$ × 10^–4 = 5 × 10^–5 M

[Cl^–] = $\frac{1}{2}$ × 10^–4 = 5 × 10^–5 M

K_ip = [Ag⁺] [Cl^–] = (5 × 10^–5)² = 2.5 × 10^–9