The electrophilic addition reactions of propene with HBr and HCl follow the same general mechanism and have similar regioselectivity. Here, I will describe the stepwise mechanism for each reaction and then compare their regioselectivity.1. Reaction of propene with HBr:Step 1: Protonation of the alkeneThe HBr molecule acts as an electrophile, and the pi bond of the propene acts as a nucleophile. The pi electrons from the double bond attack the hydrogen atom of HBr, breaking the H-Br bond and forming a new C-H bond. This results in the formation of a carbocation intermediate.CH3-CH=CH2 + H-Br CH3-CH + -CH3 + Br - Step 2: Nucleophilic attack by bromide ionThe negatively charged bromide ion Br- acts as a nucleophile and attacks the positively charged carbocation, forming a new C-Br bond.CH3-CH + -CH3 + Br - CH3-CHBr-CH3Overall reaction:CH3-CH=CH2 + HBr CH3-CHBr-CH32. Reaction of propene with HCl:Step 1: Protonation of the alkeneThe HCl molecule acts as an electrophile, and the pi bond of the propene acts as a nucleophile. The pi electrons from the double bond attack the hydrogen atom of HCl, breaking the H-Cl bond and forming a new C-H bond. This results in the formation of a carbocation intermediate.CH3-CH=CH2 + H-Cl CH3-CH + -CH3 + Cl - Step 2: Nucleophilic attack by chloride ionThe negatively charged chloride ion Cl- acts as a nucleophile and attacks the positively charged carbocation, forming a new C-Cl bond.CH3-CH + -CH3 + Cl - CH3-CHCl-CH3Overall reaction:CH3-CH=CH2 + HCl CH3-CHCl-CH3Regioselectivity comparison:Both reactions follow Markovnikov's rule, which states that the electrophile H+ in this case will add to the less substituted carbon of the alkene, resulting in the more stable carbocation intermediate. In both reactions, the carbocation is formed on the secondary carbon, which is more stable than a primary carbocation. The regioselectivity of both reactions is similar, as the major product in both cases is the halogen Br or Cl attached to the more substituted carbon of the alkene secondary carbon .In summary, the electrophilic addition reactions of propene with HBr and HCl follow the same general mechanism and have similar regioselectivity, with both reactions following Markovnikov's rule.