Q 11-11-42 E-f - Organic Chemistry (Mcmurry)

Question

Which reactant in each of the following pairs is more nucleophilic? Explain.  

F) $\mathrm{C}\equiv {\mathrm{N}}^{- }\mathrm{or} {}^{-}{\mathrm{OCH}}_3$

Step-by-Step Solution

Answer

$\mathrm{C}\equiv {\mathrm{N}}^{-}$

Nucleophile

The nucleophiles are ions possessing one electron pair. The lone electron pairs on the nucleophiles are ready to bond with each other.

Rules to identify more nucleophilic species

1. Nucleophile attacking the same atom then nucleophilicity is same as basicity that more basic species is more nucleophilic in nature.
2. Nucleophilicity increases in going down in a group of the periodic tables.

A negatively charged nucleophile is more nucleophilic than a neutral nucleophile due to a negative charge

More nucleophiles among C ≡ N -   or   - OCH 3

On the basis of:

1. Rule1: Nucleophile attacking the same atom then nucleophilicity is same as basicity that more basic species is more nucleophilic in nature.

Also on the basis of the reactivity cyanide ion is more reactive 

$\mathrm{C}\equiv {\mathrm{N}}^{-}$ is more nucleophilic than ${}^{-}{\mathrm{OCH}}_3$