Question

At 25∘C, the solubility product of Mg(OH)2 is 1.0×10−11. At which pH, will Mg2+ ions start precipitating in the form of Mg(OH)2 from a solution of 0.001MMg2+ ions ?

• A. 10
• B. 15
• C. 1
• D. 20

Answer 1

Answer: (A)

10

Answer 2

Explanation:
We know,Mg2++2OH−⇌Mg(OH)2Ksp=[Mg2+][OH−]2 (Equation for equilibrium)[OH−]=Ksp[Mg2+]=10−4∴pOH=4 and pH=10Hence, the correct answer is '10'.