Question

Given below are two statements :
Statement I : None of the alkaline earth metal hydroxides dissolve in alkali.
Statement II : Solubility of alkaline earth metal hydroxides in water increases down the group.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Statement I and Statement II both are correct.
• B. Statement I and Statement II both are incorrect.
• C. Statement I is correct but Statement II is incorrect.
• D. Statement I is incorrect but Statement II is correct.

Hint:

Trend check: For Group 2 hydroxides, solubility increases down the group. For Group 2 sulfates, solubility decreases down the group.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Alkaline earth metals (Group 2) show specific trends in the chemical properties of their compounds.
Solubility depends on the balance between hydration enthalpy and lattice enthalpy.
Step 2: Detailed Explanation:
1. Statement I: Beryllium hydroxide (\(Be(OH)_2\)) is amphoteric. It dissolves in excess alkali to form beryllate ions \([Be(OH)_4]^{2-}\). Thus, Statement I is incorrect.
2. Statement II: For Group 2 hydroxides, as we move down the group, lattice enthalpy decreases much more rapidly than hydration enthalpy. This leads to an increase in solubility. Thus, Statement II is correct.
Step 3: Final Answer:
Statement I is incorrect, but Statement II is correct.