Question

Two statements are given below
Statement I: Chlorobenzene on nitration gives 1-chloro-4-nitrobenzene as major product
Statement II: Chlorobenzene undergoes nitration slowly than benzene
Identify the correct answer

• A. Statements I, II are correct
• B. Statements I, II are incorrect
• C. Statement I correct but statement II is incorrect
• D. Statement II correct but statement I is incorrect

Hint:

In electrophilic substitution reactions, the presence of electron-donating or electron-withdrawing groups on the aromatic ring influences the reactivity and the position of substitution.

Answer 1

The Correct Option is A

- Statement I: Chlorobenzene undergoes nitration to form 1-chloro-4-nitrobenzene as the major product due to the electron-withdrawing effect of the chlorine atom, which directs the nitro group to the para position. Therefore, this statement is correct.
- Statement II: Chlorobenzene undergoes nitration more slowly than benzene because the chlorine atom, being electron-withdrawing, deactivates the ring and makes it less reactive toward electrophilic substitution. Hence, this statement is also correct. Thus, the correct answer is option (1) Statements I, II are correct.

Answer 2

Step 1: Understanding Electrophilic Substitution in Chlorobenzene
Chlorobenzene is an aromatic compound where a chlorine atom is directly attached to the benzene ring. In electrophilic substitution reactions like nitration, the substituents already present on the ring influence both the reactivity and the position where new groups get introduced.

Step 2: Evaluating Statement I
Statement I says: "Chlorobenzene on nitration gives 1-chloro-4-nitrobenzene as major product."
This is true. The chlorine atom is an electron-withdrawing group through induction but an electron-donating group via resonance. Through resonance, it increases electron density at the ortho and para positions of the ring, making them more reactive toward electrophilic attack. As a result, nitration of chlorobenzene primarily occurs at the para position due to less steric hindrance, giving 1-chloro-4-nitrobenzene (para isomer) as the major product.

Step 3: Evaluating Statement II
Statement II says: "Chlorobenzene undergoes nitration slowly than benzene."
This is also correct. Although chlorine directs electrophilic substitution to ortho and para positions due to resonance, it is overall a deactivating group. Its -I (inductive) effect pulls electron density away from the ring, making the entire ring less reactive toward electrophiles compared to unsubstituted benzene. Hence, chlorobenzene reacts more slowly than benzene during nitration.

Step 4: Final Conclusion
Both Statement I and Statement II are correct. Chlorobenzene gives 1-chloro-4-nitrobenzene as the major product upon nitration, and the reaction occurs slower than with benzene due to the deactivating nature of chlorine.