All alkali halides are soluble in water except LiF. The low solublity of LiF in water is due to its (i)______ the low solubility of CsI is due to (ii)_____. LiF is soluble in (iii)_________ solvents.

Options

A. (i) low lattice enthalpy, (ii) large hydration enthalpy, (iii) polar solvents
B. (i) high lattice enthalpy, (ii) smaller hydration enthalpy, (iii)-non-polar solvents
C. (i) high hydration enthalpy, (ii)-high lattice enthalpy, (iii)- non-polar solvents
D. (i)-smaller hydration enthalpy, (ii)-high lattice enthalpy, (iii)-polar solvents

Explanation

To solve the question regarding the solubility of alkali halides, we will fill in the blanks step by step.

### Step-by-Step Solution:

1. **Understanding the solubility of LiF**:
- The first part of the question states that the low solubility of LiF in water is due to its **(i) high lattice enthalpy**.
- Lattice enthalpy is the energy required to separate one mole of an ionic compound into its gaseous ions. In the case of LiF, both lithium (Li) and fluoride (F) ions are small, leading to a strong electrostatic attraction between them. This strong attraction requires a significant amount of energy to overcome, resulting in low solubility in water.

2. **Understanding the solubility of CsI**:
- The second part of the question states that the low solubility of CsI is due to **(ii) low hydration enthalpy**.
- Hydration enthalpy is the energy released when ions are surrounded by water molecules. CsI consists of larger ions (Cs+ and I-), which do not interact as strongly with water molecules compared to smaller ions. As a result, the energy released during hydration is not enough to compensate for the lattice energy, leading to lower solubility.

3. **Solubility of LiF in other solvents**:
- The final part of the question states that LiF is soluble in **(iii) non-polar solvents**.
- While LiF is not soluble in water due to its high lattice enthalpy, it can dissolve in non-polar solvents like ethanol or acetone. This is because non-polar solvents do not compete effectively with the strong ionic bonds in LiF, allowing some degree of solubility.

### Final Answers:
- (i) high lattice enthalpy
- (ii) low hydration enthalpy
- (iii) non-polar solvents