Question

microwave active molecule is
a.O2 b.CO2 c.HCl d.H2

Answer 1

Molecules such as HCl that have permanent dipoles are said to be microwave active. HCL is an heteronuclear molecule of hydrogen and chlorine that forms permanent dipoles that make it microwave active.
Homonuclear molecules such as H2 and O2 are generally microwave inactive.