What will be the decreasing order of basic strength of the following conjugate bases? ${ }^{-} \mathrm{OH}, \mathrm{R} \overline{\mathrm{O}}, \mathrm{CH}_{3} \mathrm{CO} \overline{\mathrm{O}}, \mathrm{C} \overline{\mathrm{l}}$

(B) $\mathrm{R} \overline{\mathrm{O}}>{ }^{-} \mathrm{OH}>\mathrm{CH}_{3} \mathrm{CO} \overline{\mathrm{O}}>\mathrm{C} \overline{\mathrm{I}}$

(A) $\mathrm{C} \overline{\mathrm{I}}>\mathrm{OH}>\mathrm{R} \overline{\mathrm{O}}>\mathrm{CH}_{3} \mathrm{CO} \overline{\mathrm{O}}$

(C) ${ }^{-} \mathrm{OH}>\mathrm{R} \overline{\mathrm{O}}>\mathrm{CH}_{3} \mathrm{CO} \overline{\mathrm{O}}>\mathrm{C} \overline{1}$

(D) $\mathrm{C} \overline{\mathrm{I}}>\mathrm{R} \overline{\mathrm{O}}>{ }^{-} \mathrm{OH}>\mathrm{CH}_{3} \mathrm{CO} \overline{\mathrm{O}}$

JEE Main · 2024 · 04 Apr 2024 · Shift 1 · Equilibrium

What will be the decreasing order of basic strength of the following conjugate bases?

^{-} OH, R \overline{O}, CH_{3} CO \overline{O}, C \overline{l}

(A) $C \overline{I} > OH > R \overline{O} > CH_{3} CO \overline{O}$
(B) $R \overline{O} >^{-} OH > CH_{3} CO \overline{O} > C \overline{I}$ ✓ Correct
(C) $^{-} OH > R \overline{O} > CH_{3} CO \overline{O} > C \overline{1}$
(D) $C \overline{I} > R \overline{O} >^{-} OH > CH_{3} CO \overline{O}$

Answer: (B)

A stronger acid has a weaker conjugate base. Acid strength:

HCl > C H_{3} COOH > H_{2} O > ROH .

Reversing gives conjugate-base strength:

R O^{-} >^{-} OH > C H_{3} CO O^{-} > C l^{-} .

Option B.

JEE Main · 2024 · 04 Apr 2024 · Shift 1 · Single correct option