Statement-I : Addition of `HBr` to `1-`butene gives two optical isomers.
Because
Statement-II : The product contains one asymmetric carbon.

Assertion: Addition of Br_(2) to 1 -butane gives two optical isomers. Reason: The product contains one asymmetric carbon atoms.

Assertion : Addition of HBr in the presence of peroxide on 1- methyl cyclopentene gives two optical isomers as major product. Reason : The major product contains two chiral carbon atoms.

Statement-I: Rate of addition of HCN on carbonyl compounds increases in presence of NaCN Because Statement-II: Reaction involves the addition of CN^(-) in rate determining step.

Statement-I: Statement-II:Birch reduction is anti addition.

Statement-I : There are two spherical nodes in 3s-orbital. Because Statement-II : There is no angular node in 3s-orbital.