The number of possibel enanntiomer pairs that can be produced during monochlorination of `2-`methylbutane is `:`

Correct Answer - A
`underset("2-Methybutane ")(CH_(3)-overset(CH_(3))overset("| ")("C ")H-CH_(2)-CH_(3))`
The monochlorinated products obtained are :
`ClCH_(2)overset(**)-overset(CH_(3))overset("| ")("C ")H-CH_(2)-CH_(3), CH_(3)-overset(CH_(3))overset("| ")underset(Cl)underset("| ")("C ")-CH_(2)-CH_(3)`
`CH_(3)-overset(CH_(3))overset("| ")("C ")Hoverset(**)-overset(Cl)overset(|)(C )H-CH_(3)` and `CH_(3)-overset(CH_(3))overset("| ")("C ")H-CH_(2)-CH_(2)Cl`
Only two monochloroderivates are optically active. Therefore possible enantimeric pairs are two, one for each.