Consider a sturated solution of silver chloride that is in contact with solid silver chloride. The solubility equilibrium can be represented as
`AgCl(s)hArrAg^(+)(aq.)+Cl^(-)(aq.)," "K_(sp)=[Ag^(+)(aq.)][Cl^(-)(aq.)]`
Where `K_(sp)` is clled the solubility product constant or simply the solubility product. In general, the solubility product of a compound is the product of the molar concentrations of the constituent ions, each raised to the power of its stoichiometric coefficient in the equilibrium equation.
For concentrations of ions that do not necessarliy correpond to equilibrium conditions we use the reaction quotient (Q) which is clled the ion or ionic prodect (Q) to predict whether a precipitate will from. Note that (Q) has the same for as `K_(sp)` are
`QltK_(sp)` Unsaturated solution
`Q=K_(sp)` Saturated solution
`Qgt_(sp)` Supersaturated solution, precipitate will from
Determine the molar solubility of `MgF_(2)` from its solubility product `K_(sp)=4xx10^(-9)` :

Options

A. `10^(-3)`
B. `6.32 xx10^(-5)`
C. `2xx10^(-5)`
D. None of these