Question

Which of the following exhibits \(-\)I effect?

• A. \(-\text{C}(\text{CH}_{3})_{3}\)
• B. \(-\text{NO}_{2}\)
• C. \(-\text{C}_{2}\text{H}_{5}\)
• D. \(-\text{CH}_{3}\)

Hint:

Alkyl groups push electrons (+I), whereas the nitro group pulls electrons strongly (-I).

Answer 1

The Correct Option is B

Step 1: Compare the options
Three of the four options are alkyl groups, and alkyl groups are electron donating.

Step 2: Why the alkyl options fail
They push electron density along the sigma bond towards the rest of the molecule (+I), which is the opposite of withdrawal.

Step 3: Select
Only $-\text{NO}_{2}$ withdraws electrons, so option (B) is correct.

Final Answer:
The $-$I group is $-\text{NO}_{2}$. \[ \boxed{\text{(B) }-\text{NO}_{2}} \]