Answer to Question #339388 in General Chemistry for Padma

Question

What is the quantity and how to dissolve silver chromate in nitric acid

Answer 1

The chemical reaction of the silver chromate dissolution is:

Ag₂CrO₄ + 2HNO₃ → 2AgNO₃ + H₂O + CrO₃

The silver chromate is sensitive to pH. In water the pH is neutral, so the crystals are not dissolving, in a basic pH there are precipitates of silver oxide and hydroxide. In acidic pH it is soluble in dilute nitric acid because the products of this reaction, silver nitrate (AgNO₃) and chromic acid CrO₃ are both soluble.

The molar solubility of silver chromate depends on the nitric acid concentration, so the desired answer cannot be precise. The $K_{sp} = 1.1 \times 10^{-12}$

$Ag_2CrO_4 = 2Ag^+ + CrO_4^{2-}$

At equilibrium the $K_{sp}$ is:

$1.1 \times 10^{-12} = x\times (2x)^2 = 4 x^3$

$x = 6.5 \times 10^{-5} M$

Where x is the concentration of silver chromate. Knowing the volume of nitric acid, the quantity of silver chromate may be deduced.