Question
Consider the following four compounds I, II, III, and IV. Choose the correct statement(s).
JEE Advanced
Chemistry
Amines
2020
JEE Advanced 2020 (Paper 2)
JEE Advanced Chemistry Question (2020) — Solution
Options
- A. The order of basicity is II > I > III > IV .
- B. The magnitude of pK b difference between I and II is more than that between III and IV .
- C. Resonance effect is more in III than in IV .
- D. Steric effect makes compound IV more basic than III .
Answer
D. Steric effect makes compound IV more basic than III .
Step-by-step solution
The correct basic strength order is (A) K b : IV > II > ∣ > III ; IV is strongest base due to SIR effect. III is weakest base due to - M group of three nitro groups present at Ortho and Para positions. Il is stronger than I since III is tertiary and I primary aromatic amine. (B) IV is found to be 40 , 000 times more basic than III . While I and II differ very little in basic strength. (C,D) Due to SIR effect in IV both - NO 2 and - N CH 3 2 will be out of plane hence resonance effect is more in III than in IV . in III than in V .
Related: Chemistry — Amines · All PYQ Banks