Few reactions of alkanes are given below. Identify the name of the reaction which is not correctly matched with the reaction.

Options

A. `CH_(3)CH_(2)CH_(2)CH_(3) overset(AlCl_(3)+HCl) to underset("Isomerisation")(CH_(3)-overset(CH_(3))overset(|)(C)H-CH_(3))`
B. `C_(6)H_(14) overset(773K)to C_(4)H_(8)+C_(2)H_(6)-`Pyrolysis
C. `CH_(4)+2O_(2)overset(Delta)to CO_(2)+2H_(2)O`-Controlled oxidation
D. `CH_(4)+HNO_(3) overset(400^(@)C)toCH_(3)NO_(2)`-Nitration

Explanation

To solve the question regarding the identification of the incorrectly matched reaction of alkanes, we will analyze each of the given reactions step by step.

### Step-by-Step Solution:

1. **Identify the First Reaction**:
- Reaction: Butane (C4H10) reacts with AlCl3 and HCl.
- Type: Isomerization.
- Explanation: Alkanes can undergo isomerization when heated in the presence of anhydrous AlCl3 and HCl, converting straight-chain alkanes to branched-chain alkanes. This reaction is correctly matched.
- Conclusion: **Correctly matched**.

2. **Identify the Second Reaction**:
- Reaction: C6H14 (hexane) upon heating forms C4H8 (butene) and C2H6 (ethane).
- Type: Pyrolysis.
- Explanation: Pyrolysis involves the thermal decomposition of organic materials at high temperatures. Higher alkanes, when subjected to pyrolysis, can break down into smaller alkanes and alkenes. This reaction is correctly matched.
- Conclusion: **Correctly matched**.

3. **Identify the Third Reaction**:
- Reaction: CH4 (methane) reacts with 2O2 to form CO2 and 2H2O.
- Type: Controlled oxidation.
- Explanation: The combustion of methane in the presence of excess oxygen leads to complete oxidation, producing carbon dioxide and water. However, this is not a controlled oxidation reaction. Controlled oxidation would involve partial oxidation leading to products like methanol or formaldehyde under specific conditions. Therefore, this reaction is incorrectly matched.
- Conclusion: **Incorrectly matched**.

4. **Identify the Fourth Reaction**:
- Reaction: Methane reacts with HNO3 at high temperature.
- Type: Nitration.
- Explanation: Nitration of methane involves its reaction with nitric acid (HNO3), which is a strong nitrating agent, leading to the formation of nitromethane (CH3NO2). This reaction is correctly matched.
- Conclusion: **Correctly matched**.

### Final Answer:
The reaction that is not correctly matched is **Option 3**: CH4 + 2O2 → CO2 + 2H2O is incorrectly labeled as controlled oxidation.

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