The reaction of with `HBr` gives

The reaction of HBr with

The reaction of HBr with gives

The reaction of HBr with gives

An alkyl halide (X) on reaction with ethanolic sodium hydroxide forms an alkene (Y) which on further reaction with HBr gives the same alkyl halide.The alkene (Y) on reaction with HBr/ peroxide followed by reaction with Mg metal followed by reaction with HCN produces an aldehyde (Z).Z is :

3 -Phenylpropene on reaction with HBr gives (as major product)