In salts of polyatomic anion, as polarising power of cation increase, thermal stability of the salt decrease and decomposed species may further undergo redox reaction
Q. Water soluble salt(x) was heated into three products A, B and C and B and C are two different paramagnetic gases. A is red in hot condition, then salt(x) is :

Options

A. `Hg(NO_(3))_(2)`
B. `FeC_(2)O_(4)`
C. `ZnSO_(4)`
D. `Pb(NO_(3))_(2)`

Explanation

To solve the question, we need to analyze the thermal decomposition of the given salts and identify which one produces the specified products: a red solid (A) and two different paramagnetic gases (B and C).

### Step-by-Step Solution:

1. **Understanding the Problem**: We need to find a water-soluble salt (X) that, when heated, decomposes into three products: one red solid (A) and two different paramagnetic gases (B and C).

2. **Identifying the Options**: The options given are:
- (1) Hg(NO3)2 (Mercury(II) nitrate)
- (2) FeC2O4 (Iron(II) oxalate)
- (3) ZnSO4 (Zinc sulfate)
- (4) Pb(NO3)2 (Lead(II) nitrate)

3. **Analyzing Each Option**:
- **Option 1: Hg(NO3)2**
Decomposes to: Hg + 2NO2 + O2
- Products: 1 solid (Hg), 2 gases (NO2 is paramagnetic, O2 is paramagnetic).
- No red solid.

- **Option 2: FeC2O4**
Decomposes to: FeO + CO2 + CO
- Products: 1 solid (FeO), 2 gases (CO2 is diamagnetic, CO is paramagnetic).
- No red solid.

- **Option 3: ZnSO4**
Decomposes to: ZnO + SO2 + O2
- Products: 1 solid (ZnO), 2 gases (SO2 is diamagnetic, O2 is paramagnetic).
- No red solid.

- **Option 4: Pb(NO3)2**
Decomposes to: PbO + 2NO2 + O2
- Products: 1 solid (PbO), 2 gases (NO2 is paramagnetic, O2 is paramagnetic).
- PbO is red when hot.

4. **Conclusion**: The only option that meets all the criteria (produces a red solid and two different paramagnetic gases) is **Pb(NO3)2**.

### Final Answer:
The water-soluble salt (X) is **Pb(NO3)2 (Lead(II) nitrate)**.

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