Question

In which one of the following, does the given amount of chlorine exert the least pressure in a vessel of capacity $1\, {dm^3}$ at $273\, K$?

• A. $0.071 \,g$
• B. $0.0355 \,g$
• C. $0.02 \,mol$
• D. $6.023 \times 10^{21}\, molecules$

Answer 1

Answer: (B)

Ideal gas equation is

$p V=n R T$

When $V$ and $T$ are same,

$p \propto n$

Thus, when number of moles, ie, $n$ is least, it will exert least pressure.

(a) $n=\frac{\text { wt }}{\text { mol. } wt }=\frac{0.0355}{35.5}=1 \times 10^{-3}\, \text { mol }$

(b) $n=\frac{0.071}{35.5}=2 \times 10^{-3}$ mol

(c) $n =\frac{\text { number of molecules }}{N_{A}}$

$=\frac{6.023 \times 10^{21}}{6.023 \times 10^{23}}=0.01$ mol

(d) $n=0.02\, mol$

Thus, $0.0355\, g$ chlorine will exert the least pressure.