Answer the following questions about the mechanism for the acid-catalyzed hydration of an alkene: a. How many transition states are there?
b. How many intermediates are there?
c. Which step in the forward direction has the smallest rate constant?

a) there are three transition states

b) there are two intermediates; carbocation and protonated alcohol

c) The first step in the forward direction

Explanation:

The acid-catalysed hydration of alkenes proceeds via a carbocation mechanism.

Three transition states can be identified in this mechanism for the acid-catalyzed hydration of alkenes.

The three transition states are derived from the three steps in the reaction sequence:

1) Protonation of the alkene by hydronium ion

2) Addition of water to the carbocation

3) loss of a proton to yield the alcohol

The first step involves the breaking of a pi bond, hence it is a slow step hence it has the smallest rate constant. The other two steps are fast steps.