Question

At 25 ∘C the reaction CaCrO4(s)←→Ca2+(aq)+CrO2−4(aq) has an equilibrium constant Kc=7.1×10−4. What is the equilibrium concentration of Ca2+ in a saturated solution of CaCrO4?

Answer 1

Answer:

2.67 × 10⁻²

Explanation:

Equation for the reaction is expressed as:

CaCrO₄(s)    ⇄      Ca₂⁺(aq)         +        CrO₂⁻⁴(aq)

Given that:

Kc=7.1×10⁻⁴

Kc= $[Ca^{2+}][CrO^{2-}_4]$

Kc= [x][x]

Kc= [x²]

7.1×10⁻⁴ =  [x²]

x = $\sqrt{7.1*10^{-4}}$

x = 0.0267

x = $2.67*10^{-2}$