Q.66. For the given molecule, "x", the preferred site for the attack of the electrophile is :
[Figur

Q: What is the correct answer for this exam Chemistry Q66?

The correct answer is D. Sol. The molecule shown is N-methyl-N-phenylformamide (or N-methylformanilide). The benzene ring has two substituents: a formyl group (-CHO) and a N-methylamino group (-N(CH₃)CHO). Let's analyze the directing effects of the substituents: 1. The formyl group (-CHO) is an electron-withdrawing group (-M and -I effect). It is a meta-director and deactivating. 2. The N-methylamino group (-N(CH₃)CHO)

Q: Q.66. For the given molecule, "x", the preferred site for the attack of the electrophile is : [Figure: A molecule with a benzene ring substituted with a nitrogen-containing group and a carbonyl…

The correct answer is D. Sol. The molecule shown is N-methyl-N-phenylformamide (or N-methylformanilide). The benzene ring has two substituents: a formyl group (-CHO) and a N-methylamino group (-N(CH₃)CHO). Let's analyze the directing effects of the substituents: 1. The formyl group (-CHO) is an electron-withdrawing group (-M and -I effect). It is a meta-director and deactivating. 2. The N-methylamino group (-N(CH₃)CHO)

Q: What are the options for this this exam Chemistry question?

A. Predominantly at "r" · B. "r" and "u" · C. "p" and "s” · D. Predominantly at "u"

Question

Q.66. For the given molecule, "x", the preferred site for the attack of the electrophile is :
[Figure: A molecule with a benzene ring substituted with a nitrogen-containing group and a carbonyl group. The nitrogen is part of a secondary amine attached to the ring, and the carbonyl is part of an aldehyde group. The positions on the ring are labeled p, r, s, u, x.]

FirstInTest · Accepted Answer

Sol. The molecule shown is N-methyl-N-phenylformamide (or N-methylformanilide). The benzene ring has two substituents: a formyl group (-CHO) and a N-methylamino group (-N(CH₃)CHO).

Let's analyze the directing effects of the substituents:
1.  The formyl group (-CHO) is an electron-withdrawing group (-M and -I effect). It is a meta-director and deactivating.
2.  The N-methylamino group (-N(CH₃)CHO) has a lone pair on nitrogen, which can donate electrons to the ring via resonance (+M effect). This makes it an ortho/para director and activating. However, the carbonyl group attached to the nitrogen also withdraws electrons, reducing the activating effect of the nitrogen. But the +M effect of N is still dominant for directing.

When there are two substituents, the activating group generally dominates the directing effect. The N-methylamino group is an ortho/para director. The positions ortho and para to the N-methylamino group are 'u' (ortho) and 's' (para).

The formyl group (-CHO) is a meta-director. The positions meta to the formyl group are 'u' and 'r'.

Let's consider the combined effect:
- The N-methylamino group directs to 'u' and 's'.
- The formyl group directs to 'u' and 'r'.

Both groups direct to position 'u'. Therefore, 'u' is the most activated site for electrophilic attack.

The solution provided in the image states: "U is predominant site towards attack of electrophile because of +M nature of nitrogen." This confirms that the nitrogen's +M effect is the dominant factor, directing to ortho/para positions, and 'u' is one such position that also aligns with meta-direction from the -CHO group.

Answer

Predominantly at "r"

Answer

"r" and "u"

Answer

"p" and "s”

Answer

Predominantly at "u"

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