Question: Order each of the following sets of compounds with respect to reactivity:

b. (CH₃)₃ CCI (CH₃)₃ CBr (CH₃)₃ COH

It is the substitution nucleophilic unimolecular reaction. It follows first-order kinetics that it is a two-step reaction in which a carbocation intermediate is formed.

The rate of the reaction depends only on the reacting species is independent of the nucleophile.

As the carbocation intermediate is formed in the reaction the reacting species which form the most stable carbocation is more reactive toward the nucleophile.

Stability of carbocation:

1. 3⁰ > 2⁰ > 1⁰
2. If carbocation showing resonance is more stable than non-resonance carbocation
3. The best leaving group forms the most stable carbocation as in halogen Br is the best-leaving group then Cl and OH is the poor leaving group.

So,

(CH₃)₃ COH < (CH₃)₃ CCI < (CH₃)₃ CBr

Reactivity order