Question

How will your separate mixture of two gases?

• A. Fractional distillation technique
• B. Graham's law of diffusion technique
• C. Osmosis
• D. Chromatography

Answer 1

The Correct Option is B

Mixture of two gases can be separated by diffusion technique. According to Graham's law of diffusion or effusion At constant temperature and pressure the rate of diffusion of a gas is inversely proportional to the square root of its density (d) or molecular mass (m) $r \propto \frac{1}{\sqrt{d}}$ or $ \frac{1}{\sqrt{M}}$ (at constant $ T$ and $P)$ $\frac{r_{1}}{r_{2}}=\sqrt{\frac{d_{2}}{d_{1}}}=\sqrt{\frac{M_{2}}{M_{1}}} \,\,[M=2 \times d]$ Thus the lighter gas will diffuse faster and the one with higher molecular mass is left behind. Fractional distillation is used to separate a mixture of a miscible liquid which differ in their boiling points e.g., $\left( C _{6} H _{6}+ CHCl _{3}\right)$ Chromatography is used to separate a mixture of miscible liquids which differ in their rate of adsorption on the stationary phase. Osmosis is the simple process of movement of only solvent molecules from the region of their higher concentration to the region of lower concentration through a semipermeable membrane.