Magnesium carbonate, mgco3, has a ksp value of 6.80*10-6. what happens when magnesium and carbonate solutions are mixed to give 2.50*10-3 m mg2 + and 2.00*10-3 m co32-?

When MgCO₃ dissolves it dissociates into the following ions

MgCO₃ - - - > Mg²⁺ + CO₃²⁻

reaction quotient (Q) = [Mg²⁺][CO₃²⁻]

ksp is the solubility product constant. If the reaction quotient > ksp the ion will precipitate, however if Q< ksp the salt will not precipitate.

First we need to calculate Q

Q = (2.5 x 10⁻³ M) (2.0 x 10⁻³ M)

Q = 5 x 10⁻⁶

ksp of salt is 6.8 x 10⁻⁶

however Q < ksp therefore salt will not precipitate.