Question

How many minimum moles of NH₃ is required to be added to 1L solution so as to dissolve 0.1 moles of AgCl (s) ?

Given :K_sp of AgCl = 10^–10&K_form of Ag(NH₃)₂⁺ = 10⁸

• A. 0.5 mol
• B. 1.0 mol
• C. 1.1 mol
• D. 1.2 mol

Answer 1

Answer: (D)

1.2 mol

Answer 2

AgCl (s) $\rightleftarrows$ Ag⁺ + Cl^–0.1(M)

Ag⁺ + 2NH₃ Ag(NH₃)₂⁺,

x 0.1(M)

\ K_form = = $\frac { 0.1 } { 10 ^ { - 9 } \times \left[ \mathrm { NH } _ { 3 } \right] ^ { 2 } }$ = 10⁸

or [NH₃] = 1 (M)

Total moles of NH₃ required = 1 + 0.1 × 2 = 1.2 moles