Alkaline earth metals and their compounds is…

Alkaline earth metals and their compounds is correct?

Single correct option

Which of the following statements about the alkaline earth metals and their compounds is correct?

A. Solubility of the sulphates decreases down the group from $\mathrm{BeSO_4}$ to $\mathrm{BaSO_4}$
B. Thermal stability of the carbonates decreases down the group
C. The hydroxides become less basic from $\mathrm{Be(OH)_2}$ to $\mathrm{Ba(OH)_2}$
D. Hydration enthalpy of the ions increases from $\mathrm{Be^{2+}}$ to $\mathrm{Ba^{2+}}$

Show answer and solution

Answer: (A) Solubility of the sulphates decreases down the group from $\mathrm{BeSO_4}$ to $\mathrm{BaSO_4}$

Sulphate solubility falls steadily because the lattice enthalpy changes little with cation size, whereas hydration enthalpy drops sharply, so

\mathrm{BeSO_4}

and

\mathrm{MgSO_4}

are soluble and

\mathrm{BaSO_4}

is practically insoluble. The other statements are reversed: carbonate stability increases down the group (larger cation polarises

\mathrm{CO_3^{2-}}

less), hydroxide basicity increases, and hydration enthalpy decreases as ionic size increases.

Original question written in the JEE Main 2024 pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake