The sum of `ppi-dpi` bonds in the gases obtained by strong heating of ferrous sulphate is :

Options

A. 1
B. 2
C. 3
D. 4

Answer

To solve the question regarding the sum of pπdπ bonds in the gases obtained by strong heating of ferrous sulfate, we will follow these steps:

### Step 1: Identify the decomposition products of ferrous sulfate (FeSO4).
When ferrous sulfate is strongly heated, it decomposes to form:
- Iron(III) oxide (Fe2O3)
- Sulfur dioxide (SO2)
- Sulfur trioxide (SO3)

### Step 2: Analyze the bonding in sulfur dioxide (SO2).
1. **Electronic Configuration**: The outermost electronic configuration of sulfur (S) in SO2 is 3S² 3P⁴.
2. **Excited State**: In the excited state, one of the paired electrons in the 3P orbital jumps to the 3D orbital, allowing for the formation of bonds.
3. **Bonding Structure**: SO2 has:
- 2 sigma bonds (one with each oxygen)
- 2 pi bonds (one from each double bond with oxygen)
- **Total pπdπ bonds**: 1 (from the interaction of p orbitals of sulfur with d orbitals of oxygen).

### Step 3: Analyze the bonding in sulfur trioxide (SO3).
1. **Electronic Configuration**: The outermost electronic configuration of sulfur in SO3 is also 3S² 3P⁴.
2. **Excited State**: In SO3, the two electrons in the 3S and 3P orbitals get excited to the 3D orbital.
3. **Bonding Structure**: SO3 has:
- 3 sigma bonds (one with each oxygen)
- 3 pi bonds (one from each double bond with oxygen)
- **Total pπdπ bonds**: 2 (from the interaction of p orbitals of sulfur with d orbitals of oxygen).

### Step 4: Calculate the total pπdπ bonds.
- From SO2: 1 pπdπ bond
- From SO3: 2 pπdπ bonds
- **Total pπdπ bonds = 1 + 2 = 3**

### Conclusion
The sum of pπdπ bonds in the gases obtained by strong heating of ferrous sulfate is **3**.