Question

The decreasing basic character of the following is:
I. $Ph{O}^{\ominus }$
II. ${CH}_3{S}^{\ominus }$
III. $\stackrel{\ominus }{O}H$
IV. $Me{O}^{\ominus }$

• A. I > II > III > IV
• B. III > IV > II > I
• C. IV > III > II > I
• D. I > II > IV > III

Answer 1

The correct option is A I > II > III > IV

Phenoxide ion is the most stable ion hence highly basic, its stability is due to the resonance,

(Refer to Image)

${C{H}_{3}S}^{⊝}$ is more basic than ${}^{⊝}OH$ due to the large size of $S$ than oxygen whereas $C{H}_3{O}^{⊝}$ is weak due to the large size of $C{H}_3$ group it causes steric hindrance.

Hence, decreasing basic character is,

$Ph{O}^{⊝}>C{H}_3{S}^{⊝}{>}^{⊝}OH>ME{O}^{⊝}$