#H_3C-CH=CH_2 + HCl rarr H_3C-C(Cl)H-CH_3#
The #2^@# alkyl halide would be the major product, as it derives from the more stable #2^@# carbocation.
Propylene is a nucleophile that first reacts with #H^+# to give a carbocation intermediate:
#H_3C-CH=CH_2 + HCl rarr H_3C-C^+H-CH_3 +Cl^-#
The alternative product of addition, #H_3C-CH_2C^+H_2#, features a primary carbocation as the intermediate (to give #H_3C-CH_2CH_2Cl#). This is a higher energy (less stable) customer than the #2^@# carbocation, and thus the reaction tends to proceed thru the lower energy #2^@# carbocation. #H_3C-C(Cl)H-CH_3# should thus be the major product of reaction.
You should check the details of this reaction with your organic chemistry text.
