In which of the following cases product will contain more number of carbon atoms than do present in reactant molecule?

Options

A.
B. `RCOOK+OH^(-)underset(CaO)overset("heat")rarrB`
C. `RCOOK+H_(2)Ooverset("Electrolysis")rarrC`
D. `RX+Naoverset(Dry ether")rarrD`

Answer

To determine in which case the product will contain more carbon atoms than the reactant molecule, we will analyze each option step by step.

### Step 1: Analyze Option A
- **Reaction**: Alkene (R-C=C-R') + H₂ → Product A
- **Process**: This is a hydrogenation reaction where hydrogen is added across the double bond of the alkene.
- **Product**: The product will be R-CH₂-CH₂-R'.
- **Carbon Count**:
- Reactant: 2 carbon atoms (from R-C=C-R')
- Product: 2 carbon atoms (from R-CH₂-CH₂-R')
- **Conclusion**: The number of carbon atoms remains the same. **Option A is incorrect.**

### Step 2: Analyze Option B
- **Reaction**: RCOOK + OH⁻ (heat) → Product B
- **Process**: This is a decarboxylation reaction, where a CO₂ group is removed.
- **Product**: The product will be RH + CO₂.
- **Carbon Count**:
- Reactant: 1 carbon (from RCOOK)
- Product: 1 carbon (from RH)
- **Conclusion**: The number of carbon atoms remains the same. **Option B is incorrect.**

### Step 3: Analyze Option C
- **Reaction**: RCOOK + H₂O (electrolysis) → Product C
- **Process**: This is an oxidative decarboxylation reaction.
- **Product**: The product will be R-R + 2 CO₂ + H₂ + KOH.
- **Carbon Count**:
- Reactant: 1 carbon (from RCOOK)
- Product: 2 carbon atoms (from R-R)
- **Conclusion**: The number of carbon atoms increases. **Option C is correct.**

### Step 4: Analyze Option D
- **Reaction**: RX + Na (dry ether) → Product D
- **Process**: This is a Wurtz reaction for the formation of higher alkanes.
- **Product**: The product will be R-R + NaX.
- **Carbon Count**:
- Reactant: 1 carbon (from RX)
- Product: 2 carbon atoms (from R-R)
- **Conclusion**: The number of carbon atoms increases. **Option D is correct.**

### Final Conclusion
From the analysis, **Options C and D** are the cases where the product contains more carbon atoms than the reactant molecule.

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