Question

Read the following passage and answer the question at the end of it.

The mixing of different gases by random molecular motion and with frequent collisions is called diffusion. A similar process in which gas molecules escape without collision through a tiny hole into a vacuum is called effusion.

1. Select the correct alternate(s).

(a) All gases spontaneously diffuse into one another when they are brought into contact.

(b) Diffusion into a vacuum will take place much more rapidly than diffusion into another gas.

(c) Both the rate of diffusion of a gas and its rate of effusion depend on its molar mass.

(d)All of the above statements are correct

2. The stopcock of the bulbs X (containing $N{H}_3$ and Y (containing HCl) are opened simultaneously. White fumes of $N{H}_{4}Cl$ are formed at point B. If AB = 36.5 cm, then BC is approximately

• A. 18 cm
• B. 25 cm
• C. 20 cm
• D. 36.5 cm

Answer 1

The correct option is B

25 cm

1. All the options are correct and are in accordance with Graham's laws.

2. AB = distance travelled by $N{H}_3$ = rate of effusion of $N{H}_3$

BC = distance travelled by HCl = rate of effusion of HCl

AB = 36.5 cm

BC = ?

According to Graham's law of effusion,

$\frac{r_{N{H}_3}}{r_{HCl}}=\sqrt{\frac{M_{N{H}_3}}{M_{HCl}}}$

$M_{N{H}_3}$ = 17.031

$M_{HCl}$ = 36.46

Substituting above vales we get,

$r_{HCl}=\sqrt{\frac{17.031}{36.46}}\times 36.5\Rightarrow BC=24.9462\approx 25cm$