3-methyl-1-hexene is reacted with hcl. select all statements below that are true for this reaction. a) reaction is stereoselective b) reaction involves carbocation intermediate c) a 1,2-shift is expected in reaction mechanism d) reaction is regioselective

The options b, c and d are True.

Explanation:

The above reaction is an example of electrophilic addition to alkenes and is  a typical reaction known as Markownikoffs addition reaction.

In the above reaction we are using Hydrogen chloride as an acid and as HCl is  a strong acid so it will provide acidic protons.

The acidic protons (H⁺) acts as electrophile and the the pi-bond in 3-methyl-1-hexene has sufficient electron density to attack the electrophilic protons. As a result of the attack hydrogen is added on one of the carbon atoms across the pi bond and a generation of carbocation takes place.

Once the carboation is formed then it rearranges into a more stable carbocation if it can and hence a stable carbocation is generated. The chloride anion can attack this stable carbocation leading to a regio-selective product.

The carbocation formed is the reaction intermediate in this case.

The statement (a) is incorrect as the above reaction involves carbocation as intermediate  and as carbocation is a planar molecule so there are two faces available for the chloride ion to attack  hence a racemic product would be formed resulting from the attack on both the sides. So the re action is not stereoselective  as not a specific isomer is formed.

The statement (b) is correct as the intermediate formed in the reaction is a carbocation.

The statement (c) is correct as carbocation is formed and we know that carbocations undergo rearrangements to form more stable carbocations so 1,2 shifts can occur in the reaction. As 1,2 shift is a way through rearrangements can occur in carbocation.

The statement (d) is correct as the reaction would lead to formation of  a stable carbocation and hence the chloride ion will only attack the stable carbocation so the reaction would be regioselective in nature.