Question

(a) Which of the following two compounds would react faster by SN

2 path way : 1 - bromobutane or

2 - bromobutane and why.?

(b) Allyl chloride is more reactive than n - propyl chloride towards nucleophilic substitution reaction. Explain why?

(c) Haloalkanes react with KCN to give alkyl cyanide as main product while with AgCN they form isocyanide as

main product. Give reason.

Answer 1

1. As 1-bromobutane is a first degree halide it is unable to form a stable carbocation, so, it will react faster by S_N2 mechanism.
2. Allyl chloride is more reactive because allyl carbocation is resonance stabilized. N-Propyl carbocation is positive inductive effect stabilized only.
3. As KCN is an ionic compound, Cl replaces CN to form KCl.