Hydrogenation of benzene is done by

Options

A. `NaBH_4`
B. `H_2/Ni`
C. HCl
D. `NaNH_2`

Answer

To solve the question regarding the hydrogenation of benzene, we can break it down into several steps:

### Step 1: Understand the Reactants
Benzene (C6H6) is an aromatic hydrocarbon known for its stability due to the delocalization of pi electrons in its ring structure.

**Hint:** Remember that benzene's stability comes from its aromatic nature, which makes it less reactive compared to aliphatic compounds.

### Step 2: Identify the Reaction Conditions
For the hydrogenation of benzene, we need to use hydrogen gas (H2) and a catalyst. In this case, nickel (Ni) is commonly used as the catalyst to facilitate the reaction.

**Hint:** Catalysts are substances that speed up a reaction without being consumed in the process.

### Step 3: Recognize the Need for Temperature Increase
Due to the stability of benzene, hydrogenation is not a straightforward process. It requires an increase in temperature to overcome the activation energy barrier for the reaction to proceed.

**Hint:** Higher temperatures can provide the necessary energy to break the stable bonds in benzene.

### Step 4: Identify the Product
The product of the hydrogenation of benzene is cyclohexane (C6H12). This compound is non-aromatic and less stable than benzene.

**Hint:** When hydrogen is added to benzene, it transforms into a saturated compound, cyclohexane.

### Step 5: Conclude the Reaction
The overall reaction can be summarized as:
\[ \text{C}_6\text{H}_6 + \text{H}_2 \xrightarrow{\text{Ni, heat}} \text{C}_6\text{H}_{12} \]

Thus, the hydrogenation of benzene is done by reacting it with hydrogen in the presence of nickel at elevated temperatures, resulting in cyclohexane.

**Final Answer:** Hydrogenation of benzene is done by hydrogen in the presence of nickel.