carbocation#!#reaction intermediate

Carbocation is a reaction intermediate in which of the following reactions?

which is the most stable carbocation formed as intermediate in nucleophilic substitution reaction ?

The carbocation is the intermediate in

Reaction Mechanism : transition state - reaction intermediates, carbocation - rearrangement and hydride shift

Carbocation as an intermediate is likely to be formed in the reaction :

A : The dehydration of ethyl alcohol in presence of Al_(2)O_(2) at 633 K gives ethene. R : The reaction proceed through the formation of carbocation intermediate.

Choose the most reasonable reaction intermediate for the following reaction.

Consider the following reaction The reactive intermediate invovled in this reaction is