Answer:
Option B
Explanation:
$\frac{n_{O_{2}}}{n_{N_{2}}}=\frac{\frac{(m_{O_{2})}}{(M_{O_{2}})}}{\frac{(m_{N_{2}})}{(M_{N_{2}})}}$
where,
$m_{O_{2}}=$ given mass of O2
$m_{N_{2}}=$ given mass of N2
$M_{O_{2}}=$ molecular mass of O2
$M_{N_{2}}=$ molecular mass of N2
$n_{O_{2}}=$ number of moles O2
$n_{N_{2}}=$ number of moles N2
$=\left[\frac{m_{O_{2}}}{m_{N_{2}}}\right]\frac{28}{32}=\frac{1}{4}\times\frac{28}{32}=\frac{7}{32}$
