How many of the following alkenes on addition of HBr would give the sae product in the presence or absence of peroxide propene, 1-butene, 2-butene, 2-methylpropene, 3-methyl-1-butene, 2,3-dimethyl-1-butene, 2-pentene, 1-pentene, 4-methyl-2-pentene

Answer

1

Explanation

Only 2-butene is symmetrical and hence gives the same product in presence or absence of peroxide.