Chemistry - GOC Question with Solution | TestHub

Explanation:

This question tests the understanding of inductive and resonance effects of various functional groups.

Inductive effect: Electron donation (+I) or withdrawal (-I) through sigma bonds.

Resonance effect: Electron donation (+R or +M) or withdrawal (-R or -M) through pi bonds or lone pairs.

Let's analyze each group:

(A) Group donate e- inductively but does not donate / withdraw by resonance

- Alkyl groups (e.g., $-{\mathrm{CH}}_2-{\mathrm{CH}}_3$) are known to donate electrons via the +I effect. They do not exhibit resonance effects.

- Therefore, (A) matches with (R) $-{\mathrm{CH}}_2-{\mathrm{CH}}_3$.

(B) Group withdraw e- inductively but does not donate / withdraw by resonance

- Groups with a positive charge, like $-{\mathrm{N}}^{+}{\mathrm{H}}_3$, strongly withdraw electrons via the -I effect. They do not have lone pairs or pi bonds to exhibit resonance.

- Therefore, (B) matches with (S) $-{\mathrm{N}}^{+}{\mathrm{H}}_3$.

(C) Group withdraw e- inductively & donate e- by resonance

- Groups like $-\mathrm{OH}$ and $-{\mathrm{NH}}_2$ contain lone pairs on the oxygen/nitrogen atom. These lone pairs can be donated via the +R (or +M) effect. However, due to the higher electronegativity of O and N compared to carbon, they also withdraw electrons inductively (-I effect).

- Therefore, (C) matches with (P) $-\mathrm{OH}$ and (T) $-{\mathrm{NH}}_2$.

(D) Group withdraw e- inductively & withdraw e- by resonance

- Groups like $-{\mathrm{NO}}_2$ contain highly electronegative atoms and multiple bonds that allow for electron withdrawal via both -I and -R (or -M) effects. The nitrogen in $-{\mathrm{NO}}_2$ is bonded to two oxygen atoms, making it electron-deficient.

- Therefore, (D) matches with (Q) $-{\mathrm{NO}}_2$.

Matching:

(A) $\to$ (R)

(B) $\to$ (S)

(C) $\to$ (P), (T)

(D) $\to$ (Q)

Final Answer: The final answer is $\boxed{B}$