Question

A polythene bag 3 litre capacity is partially filled by 1 liter of Helium gas at 0.3 atm at 300K. Subsequently, enough $Ne$ gas is filled to make total pressure 0.4 atm at 300K. Calculate ratio of moles of $Ne$ to $He$ in the container.

• A. 1/4
• B. 1/2
• C. 1/3
• D. 3/4

Answer 1

The correct option is C 1/3

Let $n$ be the moles of Helium.

Using, $PV=RTn$

$⟹0.3\times 3=0.0821\times 300\times n$

$⟹n=0.0365$ mol

Let $x$ be the moles of Neon gas

$⟹0.4\times 3=(0.0365+x)\times 0.0821\times 30$

$⟹x=0.0122$ $moles$

$\frac{MolesofNeon}{MolesofHelium}=\frac{0.0122}{0.0365}=\frac{1}{3}$