Which of the following statements are correct?
(A) Both LiCl and MgCl$$_2$$ are soluble in ethanol.
(B) The oxides Li$$_2$$O and MgO combine with excess of oxygen to give superoxide.
(C) LiF is less soluble in water than other alkali metal fluorides.
(D) Li$$_2$$O is more soluble in water than other alkali metal oxides.
Choose the most appropriate answer from the options given below

This question is about the diagonal relationship between Lithium (Li) and Magnesium (Mg). Let us analyze each statement.

Statement (A): Both LiCl and MgCl$$_2$$ are soluble in ethanol.

Due to the diagonal relationship, both Li and Mg form compounds with significant covalent character. LiCl and MgCl$$_2$$ are both covalent enough to be soluble in organic solvents like ethanol. This is correct.

Statement (B): The oxides Li$$_2$$O and MgO combine with excess of oxygen to give superoxide.

Lithium forms only the normal oxide ($$Li_2O$$) when burned in excess oxygen — it does not form peroxide or superoxide due to the small size of the $$Li^+$$ ion, which cannot stabilize the large superoxide ion $$O_2^-$$. Similarly, MgO does not form superoxides. Only heavier alkali metals like K, Rb, and Cs form superoxides. This is incorrect.

Statement (C): LiF is less soluble in water than other alkali metal fluorides.

LiF has a very high lattice energy due to the small sizes of both $$Li^+$$ and $$F^-$$ ions. The high lattice energy makes it difficult to dissolve, so LiF is the least soluble among alkali metal fluorides. This is correct.

Statement (D): Li$$_2$$O is more soluble in water than other alkali metal oxides.

Actually, alkali metal oxides generally react with water rather than simply dissolving. Among alkali metal oxides, $$Li_2O$$ reacts less vigorously with water compared to $$Na_2O$$, $$K_2O$$, etc. The solubility of alkali metal oxides increases down the group. So $$Li_2O$$ is NOT more soluble than other alkali metal oxides. This is incorrect.

The correct statements are (A) and (C) only.

The correct answer is Option A: (A) and (C) only.