Classify the following reactions as `S_(N^(1)), S_(N^(2)),E_(1) and E_(2)`:
(i) A first order reaction between an alkyl halide and alkali, to give alcohol, the order in alkali being zero.
(ii) The formation of an olefin from an alkyl halide and alkali, the reaction being first order in each of the reactants.

Explanation

(i) `R-Xoverset("Slow")rarrR^(+)+X^(-)`
`R^(+)+OH^(-)overset("Fast")rarrR-OH`
The reaction proceeds via `S_(N^(1))` mechanism, i.e.,
Rate `prop` [Alkyl halide]
(ii) Rate of reaction `prop` [Alkyl halide][Alkali]
Thus, the reaction is bimolecular. It proceeds via `E_(2)`.