Rank the alkyl halides in each group in order of increasing reactivity in an E2 reaction.

a.

b.

The hydrogen atoms replaced by distinct halogen atoms give rise to alkyl halide and are symbolized as RX.The R represents the alkyl group, and the X represents the halogen atom.

The halogen atom bonded to a primary, secondary, and tertiary carbon atom are termed primary halide, secondary halide, and tertiary halide, respectively.

In the case of a., the first structure is a tertiary halide, the second is the primary halide, and the third is the secondary halide.

For b., the first structure is a primary halide, the second is the tertiary halide, and the third is the secondary halide.

The reactivity of the tertiary alkyl halide towards the E2 reaction is the most, and for primary alkyl halide, it is the least.

The more the number of substituted groups, the more stability will be due to the +I effect on the double bond. The more the +I effect, the more stability will be.

Representation of the more substituted products

Similarly, for b., the same explanation is followed.

Representation of the more substituted products

They are ranked on the basis of E2 products formed. The alkyl halides are ranked in the following manner:

Rank for increasing reactivity in a

Rank for increasing reactivity in b