Question

Draw the products formed when is treated with each reagent: (a) (2 equiv); (b) (1 equiv)

Short answer

Hydrocarbons containing at least one carbon-carbon triple bond are called alkynes.

Alkynes are the least stable hydrocarbons and therefore have higher reactivity.

Addition reaction to triple bond on alkynes produces alkene and alkane derivatives.

Step-by-step solution

Reactivity of alkynes

Hydrocarbons containing at least one carbon-carbon triple bond are called alkynes.

Alkynes are the least stable hydrocarbons and therefore have higher reactivity.

Addition reaction to triple bond on alkynes produces alkene and alkane derivatives.

Addition of halogens to alkynes

The addition of halogens to alkynes follows the Markonikov rule by which the hydrogen is added to the least substituted carbon atom.

The addition of one equivalent of halogen produces a trans halide. This produces an alkene that can react with 1 more equivalent of halogen to form a tetrahalide.

Addition of halogen to 3-hexyne

(a) When 2 equivalents of bromine are added to 3-hexyne, a tetrahalide is formed. The reaction can be given as:

(b) When 1 equivalent of chlorine is added to 3-hexyne, a trans halide is formed. This reaction can be given as: