Q60 / 200 · NEET 2022 (Phase 2) · Chemistry

A vessel contains $3.2 \mathrm{~g}$ of dioxygen gas at STP (273.15 $\mathrm{K}$ and 1 atm pressure). The gas is now transferred to another vessel at constant temperature, where pressure becomes one third of the original pressure. The volume of new vessel in $\mathrm{L}$ is : (Given - molar volume at STP is $22.4 \mathrm{~L}$ )

  • Correct answer
    A
    6.72
  • B
    2.24
  • C
    22.4
  • D
    67.2

Solution

No. of moles of $\mathrm{O}_2=\frac{\text { Given weight of } \mathrm{O}_2}{\text { Mol. weight of } \mathrm{O}_2}$ $=\frac{3.2}{32}=0.1$ Molar vol. at $\mathrm{STP}=0.1 \times 22.4=2.24 \mathrm{~L}$ $\mathrm{P}_1=1 \mathrm{~atm}, \mathrm{~V}_1=2.24 \mathrm{~L}, \mathrm{P}_2=\frac{1}{3} \mathrm{~atm}, \mathrm{~V}_2=$ ? According to Boyle's law : $\mathrm{P}_1 \mathrm{~V}_1=\mathrm{P}_2 \mathrm{~V}_2$ $\begin{aligned} \therefore 1 \times 2.24 & =\frac{1}{3} \times \mathrm{V}_2 \\ \mathrm{~V}_2 & =2.24 \times 3 \\ & =6.72 \mathrm{~L} \end{aligned}$

Hence, the correct answer is option: 'A'.

Relevant Questions