Question

Among the following, which is insoluble in water?

• A. Sodium flouride
• B. Barium flouride
• C. Calcium flouride
• D. Magnesium flouride
• E. All are correct.

Answer 1

The correct option is D Magnesium flouride

As alkaline earth metals are divalent cations having a small radius, the charge density is high so attraction is more. Thus large energy is released. Compare to beryllium fluoride, magnesium fluoride has high lattice energy. However, Calcium flouride is sparingly soluble in water. Moreover, the fluorides of alkaline earth metals except beryllium fluoride are insoluble in water.

Hence, the correct option is D.