Question

One mole of homo triatomic gas effuse $\frac{4}{3}$ times faster than 1 mole of $C{H}_4$ under similar conditions. Select the incorrect option about the homo triatomic gas:

• A. Molar mass = 18 g/mol
• B. Density at 1 atm and 273 K = 0.4017 g/L
• C. Vapour density of the gas = 4.5
• D. None of these

Answer 1

The correct option is A Molar mass = 18 g/mol

a) We know, $\frac{r_{gas}}{r_{C{H}_4}}=\sqrt{\frac{M_{C{H}_4}}{M_{gas}}}$
$\Rightarrow \frac{4}{3}=\sqrt{\frac{16}{M_{gas}}}$
$\Rightarrow M_{gas}=9g/mol$
b) Density = $\frac{9}{22.4}=0.4017g/L$
c) Vapour density of the gas = $\frac{molecularmass}{2}=\frac{9}{2}=4.5$