Question

$KCN$ reacts readily to give a cyanide with:

• A. ethyl alcohol
• B. ethyl bromide
• C. bromobenzene
• D. chlorobenzene

Answer 1

The correct option is B ethyl bromide

The reaction will be Nucleophilic substitution

of Alkyl Halides (R-X) i.e., ethyl bromide will

react with KCN to given a cyanide

$C_2{H}_{5}Br+KCN\stackrel{alcohol}{\to }{C}_2{H}_{5}CN+KBr$

KCN is predominantly ionic and providers

cyanide ions in solution. Although both

C and N atoms are in position to donate

$c^{⊝}$ pairs, the attack takes place mainly through

carbon atoms and not through nitrogen atoms

since C-C bond is more stable than C-N bond.