Which of the folliwng is the order of the rate of reaction of `C_(6)H_(6),C_(6)D_(6)`, and `C_(6)T_(6)` towards sulphonation?

Options

A. Same rates of reactions of `C_(6)D_(6), C_(6)D_(6)` and `C_(6)T_(6)`.
B. `C_(6)T_(6) gt C_(6) D_(6) gt C_(6) H_(6)`
C. `C_(6) H_(6) gt C_(6) D_(6) gt C_(6) T_(6)`
D. `C_(6) H_(6) gt C_(6) D_(6) = C_(6) T_(6)`

Explanation

To determine the order of the rate of reaction of \( C_6H_6 \), \( C_6D_6 \), and \( C_6T_6 \) towards sulfonation, we need to analyze the bond strengths of the carbon-hydrogen (C-H) bonds in these compounds.

### Step-by-Step Solution:

1. **Understanding Sulfonation**:
- Sulfonation is a chemical reaction where a sulfonyl group (\( SO_3H \)) is introduced into an aromatic compound, such as benzene. The reaction typically involves the electrophilic substitution of hydrogen atoms on the benzene ring.

2. **Identifying the Electrophile**:
- In the case of sulfonation, the electrophile is \( SO_3 \), which attacks the benzene ring.

3. **Rate Determining Step**:
- The rate-determining step of the sulfonation reaction involves the breaking of the C-H bond in the benzene ring to allow the \( SO_3 \) to attach.

4. **Bond Strengths of Isotopes**:
- The strength of the C-H bond varies with the isotopes of hydrogen:
- \( C-H \) (in \( C_6H_6 \)) has the weakest bond strength.
- \( C-D \) (in \( C_6D_6 \)) has a stronger bond than \( C-H \).
- \( C-T \) (in \( C_6T_6 \)) has the strongest bond strength among the three.
- Therefore, the order of bond strengths is:
\[ C-T > C-D > C-H \]

5. **Rate of Reaction**:
- Since the rate of reaction is inversely related to bond strength (weaker bonds break more easily), the order of reactivity towards sulfonation will be:
- \( C_6H_6 \) (fastest reaction due to weakest bond)
- \( C_6D_6 \) (moderate reaction)
- \( C_6T_6 \) (slowest reaction due to strongest bond)

6. **Final Order**:
- Thus, the order of the rate of reaction towards sulfonation is:
\[ C_6H_6 > C_6D_6 > C_6T_6 \]

### Answer:
The order of the rate of reaction towards sulfonation is \( C_6H_6 > C_6D_6 > C_6T_6 \).

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