Question

A vessel contains two non-reactive gases; neon (monoatomic) and oxygen (diatomic). The ratio of their partial pressures is 3: 2 . Estimate the ratio of their number of molecules. Atomic mass of $Ne =20.2\, u$ and Atomic mass of $O _{2}=32\, u$

• A. $\frac{3}{2}$
• B. $\frac{2}{3}$
• C. $\frac{20.2 \times 2}{32 \times 3}$
• D. $\frac{20.2 \times 3}{32 \times 2}$

Answer 1

Answer: (A)

For a given volume of the vessel and constant temperature $P \propto \mu$.
$\mu=$ no. of moles.
$\frac{P_{1}}{P_{2}}=\frac{\mu_{1}}{\mu_{2}}=\frac{\left(N_{1} / N_{A}\right)}{\left(N_{2} / N_{A}\right)} $
$\Rightarrow \frac{N_{1}}{N_{2}}=\frac{P_{1}}{P_{2}}=\frac{3}{2}$