Question

The decreasing order of nucleophilicity among the nucleophiles is

(a) 1, 2, 3, 4 

(b) 4, 3, 2, 1

(c) 2, 3, 1, 4 

(d) 3, 2, 1, 4.

Answer 1

(d) : Strong bases are generally good nucleophile. If the nucleophilic atom or the centre is the same, nucleophilicity parallels basicity, i.e., more basic the species, stronger is the nucleophile. Hence basicity as well as nucleophilicity order is

  

Now CN^– is a better nucleophile than CH₃O^–. Hence decreasing order of nucleophilicity is