Question

Predict the major product from addition of HBr to each of the following alkenes:

Short answer

(a)

(b)

(c)

Step-by-step solution

Addition reaction of alkene

In the addition reaction of alkene, addition of proton (H⁺) takes place then it led to formation of carbocation.

If the formed carbocation is not stable then rearrangement of take place to form more stable carbocation

In the second step addition of nucleophile (Br^-) takes place.

Formation of product

Addition of proton leads to formation of secondary carbocation. Then at last addition of bromine takes place and leading to the formation of product. The addition takes place according to Markownikov’s rule.

 Step 3: Formation of product

Addition of proton takes place leading to the formation of a tertiary carbocation. acts as a nucleophile to give the final product. The addition follows Markownikov’s rule.

Formation of product

Addition of proton takes place leading to the formation of carbocation. Rearrangement takes place to give more stable tertiary carbocation. Br^-acts as a nucleophile to give the final product. The reaction follows Markownikov’s rule.