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 of the given reactions the product contains more carbon atoms than the reactants, we will analyze each option step by step.

### Step 1: Analyze the first option
- **Reaction**: Substituted alkene + H₂ (hydrogenation)
- **Reactant**: RCH=CHR' (2 carbon atoms from the double bond and 1 carbon from each alkyl group)
- **Product**: RCH₂-CH₂R' (after hydrogenation)
- **Carbon Count**:
- Reactant: 4 carbon atoms (2 from the double bond and 2 from R and R')
- Product: 4 carbon atoms (same as reactant)

**Conclusion**: The number of carbon atoms in the product is equal to that in the reactant. This option is incorrect.

### Step 2: Analyze the second option
- **Reaction**: Potassium salt of carboxylate + heating + CaO (decarboxylation)
- **Reactant**: RCOOK (1 carbon from R and 1 from COOK)
- **Product**: RCH₃ (alkane) + CO₂
- **Carbon Count**:
- Reactant: 2 carbon atoms (1 from R and 1 from COOK)
- Product: 2 carbon atoms (1 from R and 1 from CO₂)

**Conclusion**: The number of carbon atoms in the product is equal to that in the reactant. This option is incorrect.

### Step 3: Analyze the third option
- **Reaction**: Potassium salt of carboxylate + water + electrolysis (Colby electrolytic method)
- **Reactant**: RCOOK (1 carbon from R and 1 from COOK)
- **Product**: Alkane + 2CO₂ + K₂O
- **Carbon Count**:
- Reactant: 2 carbon atoms (1 from R and 1 from COOK)
- Product: 4 carbon atoms (1 from R and 2 from 2CO₂)

**Conclusion**: The product has more carbon atoms than the reactant. This option is correct.

### Step 4: Analyze the fourth option
- **Reaction**: Alkyl halide + Na (Wurtz reaction)
- **Reactant**: R-X (1 carbon from R and 1 from X)
- **Product**: R-R + NaX (alkane)
- **Carbon Count**:
- Reactant: 2 carbon atoms (1 from each alkyl halide)
- Product: 2 carbon atoms (1 from each R)

**Conclusion**: The number of carbon atoms in the product is equal to that in the reactant. This option is incorrect.

### Final Conclusion
The only option where the product has more carbon atoms than the reactant is **Option C** (Colby electrolytic method).

### Summary of Correct Options
- **Correct Options**: C (Colby electrolytic method) and D (Wurtz reaction).