Answer
(e) $0.77$
Work Step by Step
Recall relation between mole fraction and mass fraction. For a component $i$: $$w_i=\frac{x_iM_i}{M_{mix}},$$ where
$w_i$ = mass fraction
$x_i$ = mole fraction
$M_i$ = molar mass of component
$M_{mix}$ = apparent molar mass of mixture
We plug in given data: $$\begin{aligned}
w_{N_2}&=\frac{0.55\cdot 28}{20}=0.77
\end{aligned}$$ The correct answer is (e) $0.77$.
