Question

structure of the major products of ethynylcyclohexane + excess HBr with proper configuration

Answer 1

It is given that, ethynylcyclohexane reacting with excess HBr

Here, In this reaction firstly first hydrogen will replace by Bromine and then other of same place we get gem di halide.

So, final product is 1,1-Dibromo-1-cyclohexylethane