What is the number of mole(s) of `H_(2)(g)` required to saturate one mole benzene ?

Options

A. 1
B. 2
C. 3
D. 4

Answer

To determine the number of moles of \( H_2(g) \) required to saturate one mole of benzene, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Benzene Structure**:
Benzene (\( C_6H_6 \)) is an aromatic hydrocarbon with a ring structure that contains alternating double bonds. This structure makes benzene an unsaturated hydrocarbon.

2. **Identifying the Unsaturation**:
Each double bond in benzene represents an unsaturation. Benzene has three double bonds, which means it has three pi bonds that need to be converted to single bonds to achieve saturation.

3. **Hydrogenation Process**:
To saturate benzene, we need to perform hydrogenation, which involves adding hydrogen (\( H_2 \)) across the double bonds. Each \( H_2 \) molecule contributes two hydrogen atoms.

4. **Calculating the Number of \( H_2 \) Molecules Needed**:
- Since there are three double bonds in benzene, we need to break these three pi bonds.
- Each pi bond broken requires one \( H_2 \) molecule to add two hydrogen atoms.
- Therefore, to saturate all three double bonds, we need 3 \( H_2 \) molecules.

5. **Final Calculation**:
- Since each \( H_2 \) molecule contains 2 hydrogen atoms, and we need a total of 6 hydrogen atoms to saturate one mole of benzene, we can confirm that:
\[ \text{Number of moles of } H_2 = 3 \text{ moles} \]

### Conclusion:
Thus, the number of moles of \( H_2(g) \) required to saturate one mole of benzene is **3 moles**.

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