Question

Which of the following represents the correct order of reactivity in the given nucleophilic substitution reactions? (Choose the correct option)
i) \( \text{Sodium acetate} \rightarrow \) Cyclohexane.
ii) \( \text{KCl} \rightarrow \) Cyclohexane.
iii) \( \text{CH}_3\text{OH} + \text{Cl} \rightarrow \) New compound.
iv) \( \text{CH}_3\text{CN} \rightarrow \) Cyclohexane via substitution.

• A. I<III<II<IV
• B. I<III<IV<II
• C. I<IV<III<II
• D. II<III<IV<I

Hint:

In nucleophilic substitution reactions, the reactivity typically follows the trend of the strength of the nucleophile and the leaving group. Stronger nucleophiles and better leaving groups tend to increase reactivity.

Answer 1

The Correct Option is D

Step 1: Understanding the Question.
The question asks for the order of reactivity in nucleophilic substitution reactions. We are given four reactions involving various substrates and conditions. Let's break them down.
Step 2: Analyzing the Reactions.
- (i) \( \text{Sodium acetate} \rightarrow \) Cyclohexane: This is an elimination reaction, which is generally slower than substitution reactions.
- (ii) \( \text{KCl} \rightarrow \) Cyclohexane: This is a simple substitution reaction. However, it proceeds with moderate reactivity as the leaving group is chloride.
- (iii) \( \text{CH}_3\text{OH} + \text{Cl} \rightarrow \) New compound: This is a substitution reaction, and the presence of methanol (a better solvent) and chloride makes it more reactive.
- (iv) \( \text{CH}_3\text{CN} \rightarrow \) Cyclohexane via substitution: Cyanide (CN) is a very strong nucleophile, making this reaction proceed with high reactivity.
Step 3: Conclusion.
The correct order of reactivity is (D) II<III<IV<I.