The relation between pressure exerted by an ideal gas `(p_("ideal"))` and observed pressure `(p_("real"))` is given by the equation,
`p_("ideal")=p_("real")+ (an^(2))/V^(2)`
(i) If pressure is taken in `NM^(-2)`, number of moles in mol and volume in `m^(3)`, calculate the unit of 'a'.
(ii) What will be the unit of 'a' when pressure is in atmosphere and volume in `dm^(3)`?

Explanation

Given that, `p_("real") = p_("real") + (an^(2))/(V^(2))`
`a = (pV^(2))/(n^(2))`. If units of `p = Nm^(-2)`, units of `V = m^(2)`, units of n = mol
Then, units of a `= (Nm^(-2) (m^(3))^(2))/((mol)^(2)) = Nm^(4) mol^(2)`