Question

Question #2e817

Answer 1

Dissolution value is the molar solubility of the substance which is the molar concentration of a saturated solution. This is calculated from the `K_(sp)` value.

Let's say you have a solid that is dissolving

`A_xB_y(s)rarr x A(aq)+ yB(aq)`

`K_(sp)=[A]^x[B]^y`

So in your example

`Ag_2CrO_4(s) rarr2Ag^+(aq)+CrO_4^(-) (aq)` and

`K_(sp)=[Ag^+]^2[CrO_4^(-)]`

The dissolution value will be the concentration of the chromate ion (this will also be the concentration of the solution). Each formula unit of the compound dissociates into 2 silver ions and 1 chromate ion so the concentration of silver ions will be double that.

Mathematically, the `K_(sp)` value

`K_(sp)=[Ag^+]^2[CrO_4^(-)]`

`K_(sp)=[2(3.2*10^(-5))]^2[3.2*10^(-5)] = 1.3*10^(-13)`

Answer 2

`K_"sp" = 1.31 ×10^(-13)`

Explanation:

`K_"sp" = 1.31 ×10^(-13)`

Every mole of Ag₂CrO₄ that dissolves forms 2 mol of Ag⁺ and 1 mol of CrO₄²⁻.

`K_"sp" = ["Ag"^+]^2["CrO"_4^(2-)] = (6.4 × 10^(-5))^2(3.2 × 10^-5) = 1.31 ×10^(-13)`