Question

Order nucleophilicity
(i) $\mathrm{OH}{}^{-}$
(ii) $\mathrm{HS}{}^{-}$
(iii) $\mathrm{PH}-\mathrm{O}{}^{-}$
(iii) $\mathrm{C}{}_2\mathrm{H}{}_5-\mathrm{O}{}^{-}$

• A. i > ii > iii > iv
• B. ii > iv > i > iii
• C. ii > iii > i > iv
• D. iii > iv > i > ii

Answer 1

Answer: (B)

Order of nucleophilicity
$\mathrm{OH}{}^{-},\mathrm{HS}{}^{-},\mathrm{Ph}-\mathrm{O}{}^{-},\mathrm{C}{}_2\mathrm{H}{}_5\mathrm{O}{}^{-}=\mathrm{HS}{}^{-}>\mathrm{C}{}_2\mathrm{H}{}_5\mathrm{O}{}^{-}>\mathrm{OH}{}^{-}>\mathrm{Ph}-\mathrm{O}{}^{-}$
On increasing delocalization of e- nucleophilicity decrease