Option A: "Solubility of carbonates in water decreases down the group." For alkaline earth metals (Group 2): The solubility of carbonates (MCO3) actually decreases down the group because lattice energy decreases more slowly than the hydration energy. This statement is correct. Option B: "All the sulphates are thermally stable." For sulphates (MSO4) of alkaline earth metals: All of them are thermally stable, i.e., they do not decompose easily on heating. This statement is correct. Option C: "All the nitrates decompose on heating." For nitrates (M(NO3)2) of group 2: All nitrates decompose on heating to give oxides, nitrogen dioxide, and oxygen.
This statement is correct. Option D: "All halides are ionic in nature." For halides ( MX2 ): Most are ionic, but BeCl2 (beryllium chloride) has covalent character due to the small size and high polarizing power of Be2+. This statement is incorrect. Final Answer: Option D - All halides are ionic in nature (Incorrect statement).