Halogenation of alkanes is

Options

A. A reductive process
B. An oxidative process
C. An isoathermal process
D. An edothermic process

Answer

**Step-by-Step Solution:**

1. **Understanding Halogenation of Alkanes:**
Halogenation refers to the process of adding halogen atoms (like fluorine, chlorine, bromine, or iodine) to alkanes. Alkanes are saturated hydrocarbons that contain only single bonds (sigma bonds) between carbon atoms.

2. **Mechanism of Halogenation:**
The halogenation of alkanes occurs via a free radical mechanism, which typically requires energy input, often in the form of light or heat. This process involves the breaking of the halogen bond and the formation of free radicals.

3. **Example Reaction:**
For instance, when methane (CH₄) reacts with chlorine (Cl₂) under light, one hydrogen atom from methane is replaced by a chlorine atom. The reaction can be represented as:
\[ CH_4 + Cl_2 \xrightarrow{light} CH_3Cl + HCl \]
Here, chloromethane (CH₃Cl) is formed along with hydrogen chloride (HCl).

4. **Oxidation and Reduction:**
In this reaction, we need to analyze the oxidation states:
- In methane (CH₄), carbon has an oxidation state of -4.
- In chloromethane (CH₃Cl), carbon has an oxidation state of -2.
- Chlorine in Cl₂ has an oxidation state of 0, while in HCl, it has an oxidation state of -1.

The change in oxidation states indicates that the carbon is oxidized (increase in oxidation state from -4 to -2), while chlorine is reduced (decrease in oxidation state from 0 to -1).

5. **Thermodynamics of the Reaction:**
The halogenation process is exothermic, meaning it releases energy. This is contrary to the idea of it being endothermic (which would imply heat absorption). The reaction is also isothermal, meaning it can occur at a constant temperature.

6. **Conclusion:**
Therefore, the halogenation of alkanes is primarily an oxidative process because it involves an increase in the oxidation state of carbon. The correct answer to the question is that halogenation of alkanes is an oxidative process.