Which one of the following chlorides has maximum tendency to from hydrate ?

Options

A. `BaCl_(2)`
B. NaCl
C. `MgCl_(2)`
D. LiCl

Answer

To determine which chloride has the maximum tendency to form hydrates, we need to analyze the cations present in the given chlorides: BaCl2, NaCl, MgCl2, and LiCl. The tendency to form hydrates is influenced by the size and charge of the cation in each compound.

### Step-by-Step Solution:

1. **Identify the Cations**:
- BaCl2 contains Ba²⁺ (Barium ion)
- NaCl contains Na⁺ (Sodium ion)
- MgCl2 contains Mg²⁺ (Magnesium ion)
- LiCl contains Li⁺ (Lithium ion)

2. **Analyze the Cation Sizes**:
- Cation size is crucial because smaller cations can attract water molecules more effectively due to their higher charge density.
- As we move down a group in the periodic table, the size of the cations increases.
- Therefore, we can compare the sizes:
- Li⁺ < Na⁺ < Mg²⁺ < Ba²⁺

3. **Consider the Charge of the Cations**:
- Cations with higher positive charges tend to attract water molecules more strongly.
- Mg²⁺ and Ba²⁺ have a +2 charge, while Na⁺ and Li⁺ have a +1 charge.
- The higher charge of Mg²⁺ compared to Na⁺ and Li⁺ contributes to a stronger attraction for water molecules.

4. **Determine the Hydration Tendency**:
- The hydration tendency increases with smaller size and higher charge.
- Among the cations, Mg²⁺ is the smallest and has a higher charge than Na⁺ and Li⁺.
- Although Ba²⁺ has a +2 charge, it is larger than Mg²⁺, which reduces its ability to attract water molecules.

5. **Conclusion**:
- Therefore, MgCl2, which contains the Mg²⁺ cation, has the maximum tendency to form hydrates due to the small size and high charge of the magnesium ion.

### Final Answer:
**MgCl2 has the maximum tendency to form hydrates.**