Question

Compare the solubilities of Mg(OH)2 in 0.1 M NH3 and in pure water. Neglect

the activity coefficients. ,
Ksp,Mg(OH)2 = 1.8 × 10−11
Kb,NH3 = 1.75 × 10−5


Answer: The solubility of Mg(OH)2 in 0.1 M NH 3 is 16 times lower than the
solubility in pure water 48

Answer 1

The solubility of Mg(OH)2 is 16 times lower in 0.1 M NH3 compared to pure water due to the complex formation with NH3.

Step-by-step explanation:

The solubility of Mg(OH)2 in 0.1 M NH3 is 16 times lower than its solubility in pure water.

This is because NH3 is a weak base and can react with Mg(OH)2 to form a complex ion, Mg(NH3)42+.

This complex ion reduces the concentration of Mg2+ and OH- ions in the solution, thereby decreasing the solubility of Mg(OH)2.