$(a)\,\,CH_3CO_2^-$ $(b)\,\,H_2O$
$(c)\,\,CH_3SO_3^-$ $(d)\,\,\bar OH$
ione pair donating tendency on oxygen is reduced, nucleophilicity reduced $b < c < a < d$
$(II)\,\,\,{{H}_{2}}C=CH-C{{H}_{2}}-\overset{+}{\mathop{C}}\,H-C{{H}_{3}}$
$(III)\,\,\,\begin{matrix}
\,\,\,\,\,C{{H}_{3}}\, \\
|\, \\
{{H}_{3}}C-C-\overset{+}{\mathop{C}}\,{{H}_{2}} \\
|\, \\
\,\,\,C{{H}_{3}} \\
\end{matrix}$
$(i)\,\,RC \equiv \mathop C\limits^ \ominus $
$(ii)\,\,[IMAGE]$
$(iii)\,\,{R_2}C = \mathop C\limits^ \ominus H$
$(iv)\,\,{R_3}C - \mathop C\limits^ \ominus {H_2}$
$\mathop {{H_3}C\mathop C\limits^ \ominus {H_2}}\limits_{(i)} \,,$$\mathop {{H_2}C = \mathop C\limits^ \ominus H}\limits_{(ii)} $ અને $\mathop {H - C \equiv \mathop C\limits^ \ominus }\limits_{(iii)} $