Assertion: The compressibility factor for `H_(2)` and `He` is
`[1+(bP)/(RT)]`
Reason: The compressibility factor `H_(2)` and `He` can be derived from van der Waal's equation.

Explanation

`[P+(a)/V^(2)][V-b]=RT` ,for `H_(2)` and He a is very small because of low mol wt
Thus `PV =RT +Pb`
`Z =(PV)/(RT)=[1+(Pb)/(RT)]` .