On sulphonation of `C_6H_5 Cl`

Options

A. Benzene sulphonic acid is formed
B. Metachlorobenze sulphonic acid is formed
C. Orthochlorobenzene sulphonic acid is formed
D. Orth and para chlorobenzene sulphonic acids are formed

Explanation

To solve the question regarding the sulfonation of chlorobenzene (C6H5Cl), we will follow these steps:

### Step 1: Understand the Structure of Chlorobenzene
Chlorobenzene is a benzene ring (C6H5) with a chlorine atom (Cl) attached to it. The presence of the chlorine atom affects the electron density of the benzene ring due to its electronegativity.

**Hint:** Remember that chlorine is an electron-withdrawing group due to its -I (inductive) effect.

### Step 2: Identify the Effects of Chlorine on the Benzene Ring
Chlorine has a -I effect, which means it pulls electron density away from the carbon it is attached to. However, chlorine also has lone pairs that can participate in resonance, which can donate electron density back to the ortho and para positions of the benzene ring.

**Hint:** Consider both the inductive effect and resonance effect when analyzing how chlorine influences the reactivity of the benzene ring.

### Step 3: Determine the Electrophile in Sulfonation
In the sulfonation reaction, sulfur trioxide (SO3) acts as the electrophile. The electrophilic attack will occur at the positions of the benzene ring where electron density is highest, which are the ortho and para positions relative to the chlorine atom.

**Hint:** Identify the electrophile in the reaction and think about where it will attack on the benzene ring.

### Step 4: Predict the Products of the Reaction
When SO3 attacks the chlorobenzene, it can do so at the ortho and para positions, leading to the formation of two products:
1. Ortho-chlorobenzenesulfonic acid
2. Para-chlorobenzenesulfonic acid

**Hint:** Visualize the possible resonance structures to determine where the electrophile can attack.

### Step 5: Analyze the Given Options
Now we will evaluate the options provided:
- **Option A:** Benzene sulfonic acid - Incorrect, as this does not contain chlorine.
- **Option B:** Meta-chlorobenzenesulfonic acid - Incorrect, as the meta position does not have increased electron density due to chlorine.
- **Option C:** Ortho-chlorobenzenesulfonic acid - Partially correct, but does not account for the para product.
- **Option D:** Ortho and para-chlorobenzenesulfonic acid - Correct, as both products are formed.

**Hint:** Cross-check the products formed with the options given to find the correct answer.

### Conclusion
The correct answer to the question is **Option D: Ortho and para-chlorobenzenesulfonic acid are formed** during the sulfonation of chlorobenzene.