Question

What is the correct order of C-X bond strength in CH\(_3\)-X?

• A. \( \text{CH}_3\text{F}>\text{CH}_3\text{Cl}>\text{CH}_3\text{Br}>\text{CH}_3\text{I} \)
• B. \( \text{CH}_3\text{F}>\text{CH}_3\text{Br}>\text{CH}_3\text{Cl}>\text{CH}_3\text{I} \)
• C. \( \text{CH}_3\text{Cl}>\text{CH}_3\text{Br}>\text{CH}_3\text{I}>\text{CH}_3\text{F} \)
• D. \( \text{CH}_3\text{I}>\text{CH}_3\text{Br}>\text{CH}_3\text{Cl}>\text{CH}_3\text{F} \)

Hint:

In C-X bonds, the bond strength decreases as the size of the halogen increases. The C-F bond is the strongest, and the C-I bond is the weakest.

Answer 1

The Correct Option is A

Step 1: Understanding bond strengths.
The bond strength decreases as we move from fluorine to iodine in the halogen series due to the increasing atomic size and bond length. The C-F bond is the strongest, and the C-I bond is the weakest.

Step 2: Analyzing the options.
(A) \( \text{CH}_3\text{F}>\text{CH}_3\text{Cl}>\text{CH}_3\text{Br}>\text{CH}_3\text{I} \): Correct — The bond strength decreases as we move down the halogen group.
(B) \( \text{CH}_3\text{F}>\text{CH}_3\text{Br}>\text{CH}_3\text{Cl}>\text{CH}_3\text{I} \): Incorrect — This does not follow the expected trend.
(C) \( \text{CH}_3\text{Cl}>\text{CH}_3\text{Br}>\text{CH}_3\text{I}>\text{CH}_3\text{F} \): Incorrect — This is the reverse of the correct order.
(D) \( \text{CH}_3\text{I}>\text{CH}_3\text{Br}>\text{CH}_3\text{Cl}>\text{CH}_3\text{F} \): Incorrect — This is the reverse of the correct order.

Step 3: Conclusion.
The correct answer is (A) \( \text{CH}_3\text{F}>\text{CH}_3\text{Cl}>\text{CH}_3\text{Br}>\text{CH}_3\text{I} \).