Rank the following in order of increasing nucleophilicity, putting the least nucleophilic first. $$\begin{array} { c c c c }
\mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { O } ^ { - } & \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm {~S} ^ { - } & \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { OH } & \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { SH } \
\text { I } & \text { II } & \text { III } & \text { IV }
\end{array}$$

Question

Rank the following in order of increasing nucleophilicity, putting the least nucleophilic first. $$\begin{array} { c c c c } 
\mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { O } ^ { - } & \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm {~S} ^ { - } & \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { OH } & \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { SH } \
\text { I } & \text { II } & \text { III } & \text { IV }
\end{array}$$

Quizplus · Accepted Answer

The order of nucleophilicity is determined by the ability to donate electrons. Alcohols (III) are less nucleophilic than thiols (IV) due to the higher electronegativity of oxygen compared to sulfur. Among the anions, alkoxide (I) is less nucleophilic than thiolate (II) for the same reason.

Rank the Following in Order of Increasing Nucleophilicity, Putting the Least