The product formed by the electrophilic addition of HBr to propene is 2-bromopropane.Here is the complete mechanism for the reaction:1. Protonation of the alkene propene by HBr:The alkene propene acts as a nucleophile and attacks the hydrogen atom of HBr, which acts as an electrophile. This leads to the formation of a carbocation intermediate and a bromide ion Br- . The carbocation is formed at the more substituted carbon secondary carbocation due to its greater stability compared to a primary carbocation.Propene + HBr -> [CH3-CH + -CH3] + Br-2. Nucleophilic attack by the bromide ion:The bromide ion Br- acts as a nucleophile and attacks the carbocation, forming a bond with the positively charged carbon atom.[CH3-CH + -CH3] + Br- -> CH3-CH Br -CH3The final product is 2-bromopropane.