Question

The Ksp for BaCO₃ is 1.6 x 10^-9 .

A)Write a chemical equation for the equilibrium of BaCO₃ (s) with its ions.

B) When 20.0 mL of a 0.10 M Ba(NO₃)₂ is added to 50.0 mL of a 0.10 M Na₂CO₃ calculate the reaction quotient and determine if a precipitate will form?

C) For the same reaction, predict the direction the system once it gets to equilibrium will shift when acid is added to the system.

Answer 1

(a)

The chemical equation is:

BaCO3(s) ---> Ba²⁺(aq) + CO₃^2-(aq)

(b)

The reaction quotient is:

Q = [Ba²⁺]*[CO₃^2-] = [0.1/3.5]*[0.1/1.4] = 0.00204

Since Q > K_sp, so the precipitate will form.

(c)

When system is at equilibrium, and if acid is added, [H⁺] will increase, which means the weak acid H₂CO₃ will form by consuming the carbonate ions. This will cause the system to go towards left, so the ppt will dissolve and more of the Ba²⁺ and CO₃^2- ions will get into the solution.

Hope this helps !