Question

For gases $C{H}_4\left(g\right)$ and $N_2\left(g\right)$ Both gases are in the same sealed flask with a total pressure of 750 mmHg. The partial pressure of $N_2\left(g\right)$ is 500 mmHg. Which is / are incorrect graph.

• A.
• B.
• C.
• D.

Answer 1

Answer: (A), (C), (D)

Use maxwell-Boltzmann's distribution of molecular velocity curve or equation.
The maxwell equation is:
$\frac{dN}{N}={\left(\frac{m}{2\pi k_{B}T}\right)}^{\frac{1}{2}}{e}^{\frac{-m{v}^2}{2k_{B}T}}dV$
By analyzing above equation we can find the correct graph.

A) $C{H}_4$ has greater most probable velocity than $N_2$ since it is lighter in mass and also number of molecules of $N_2$ is more than that of $C{H}_4$ since it has more partial pressure.

B) Heavier molecules have small distribution since they move slowly and lighter molecules have broad distribution. Also number of molecules of $N_2$ is more than that of $C{H}_4$ since it has more partial pressure.

C) $C{H}_4$ has greater most probable velocity than $N_2$ since it is lighter in mass.

D) Partial pressure of $N_2$ gas is more than $C{H}_4$. Hence the graph D is wrong.