Question

The decreasing order of reactivity of the following organic molecules towards $AgNO_3$ solution is

• A. (B) > (A) > (C) > (D)
• B. (A) > (B) > (D) > (C)
• C. (A) > (B) > (C) > (D)
• D. (C) > (D) > (A) > (B)

Answer 1

Answer: (A)

(B) > (A) > (C) > (D)

Answer 2

Reactivity towards $AgNO_3$ is an $SN1$ reaction, dependent on carbocation stability.

1. (B): Forms a carbocation highly stabilized by the +M effect of the $-OMe$ group. (Most stable)
2. (A): Forms an allylic carbocation. Despite ring strain, allylic resonance provides significant stabilization, making it more stable than a simple secondary carbocation.
3. (C): Forms a simple secondary carbocation, stabilized by hyperconjugation.
4. (D): Forms a secondary carbocation destabilized by the strong -I effect of the $\beta$-$NO_2$ group. (Least stable)

Therefore, the decreasing order of reactivity is (B) > (A) > (C) > (D).