Question

You are browsing through the Handbook of hypothetical chemistry when you come across a solid that is reported to have a ${\mathbf{\text{K}}}_{\mathbf{\text{sp}}}$value of zero in water at ${\mathbf{25}}^{\mathbf{\circ }}\mathbf{\text{C}}$. What does this mean?

Short answer

The solid having zero ${\text{K}}_{\text{sp}}$value means that the solid is insoluble in water at ${25}^{\circ }\text{C}$.

Step-by-step solution

Definition of the basic equilibrium constant

The solubility product constant is the basic equilibrium constant that is well defined for equilibrium among a solid and its respective ions in the solution.

Calculation to find which is more likely to dissolve in an acidic solution

The soluble equilibrium of the salt AB is

$\text{AB(s)}\to {\text{A}}^{\text{+}}\text{(aq)}+{\text{B}}^{\text{-}}\text{(aq)}$

Expression for the solubility product is

${\text{K}}_{\text{sp}}=\left[{\text{A}}^{\text{+}}\right]\left[{\text{B}}^{\text{-}}\right]$

Solid having zero solubility product value means that the solid is not soluble in water at${25}^{\circ }\text{C}$

The solubility product is nothing but the product of the concentration of the ions present in the solution. When the solid has zero value, it has zero ${\mathbf{\text{K}}}_{\mathbf{\text{sp}}}$ molar concentrations of ions.