Assertion: Increasing order of covalent character among given compounds is `HgCl_(2)ltCdCl_(2)ltZnCl_(2)`
Reason: Order of size of cations is `Zn^(2+)ltCd^(2+)ltHg^(2+)` .

Options

A. If both assertion and reason are true and the reason is the correct explanation of assertion
B. If both assertion and reason are true and the reason is not the correct explanation of assertion
C. If assertion is false but reason is true
D. If assertion is true but the reason is false

Answer

To solve the assertion and reason question, we will analyze both the assertion and the reason step by step.

### Step 1: Analyze the Assertion
The assertion states that the increasing order of covalent character among the given compounds is:
\[ \text{HgCl}_2 < \text{CdCl}_2 < \text{ZnCl}_2 \]

**Covalent Character**: The covalent character of a compound generally increases with the decrease in size of the cation. Smaller cations can polarize the electron cloud of the anion more effectively, leading to greater covalent character.

### Step 2: Analyze the Cation Sizes
According to the assertion, the order of the cation sizes is:
\[ \text{Hg}^{2+} > \text{Cd}^{2+} > \text{Zn}^{2+} \]

This means that:
- **Hg²⁺** is the largest cation
- **Cd²⁺** is intermediate
- **Zn²⁺** is the smallest cation

### Step 3: Determine the Correct Order of Covalent Character
Since smaller cations have greater covalent character, we can conclude:
- **ZnCl₂** should have the highest covalent character because Zn²⁺ is the smallest.
- **CdCl₂** will have a moderate covalent character.
- **HgCl₂** will have the lowest covalent character because Hg²⁺ is the largest.

Thus, the correct order of covalent character should be:
\[ \text{ZnCl}_2 > \text{CdCl}_2 > \text{HgCl}_2 \]

### Step 4: Conclusion on Assertion
Since the assertion claims the opposite order (\(\text{HgCl}_2 < \text{CdCl}_2 < \text{ZnCl}_2\)), it is **false**.

### Step 5: Analyze the Reason
The reason states that the order of size of cations is:
\[ \text{Zn}^{2+} < \text{Cd}^{2+} < \text{Hg}^{2+} \]

This is indeed true as the size of cations increases down the group in the periodic table. Therefore, the reason is **true**.

### Final Conclusion
- The assertion is **false**.
- The reason is **true**.

Thus, the correct option would be that the assertion is false and the reason is true.

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