Pressure exerted by an ideal gas on the walls of the container is...

The pressure exerted by an ideal gas is given by $P = \dfrac{1}{3} \rho v_{rms}^2$, where $\rho$ is the density of the gas and $v_{rms}$ is the root mean square velocity.

The mean kinetic energy per unit volume is given by $E = \dfrac{1}{2} \rho v_{rms}^2$.

From these two equations, we can write $P = \dfrac{2}{3} \left( \dfrac{1}{2} \rho v_{rms}^2 \right) = \dfrac{2}{3} E$.

Therefore, the pressure exerted by an ideal gas is equal to two-thirds of the mean kinetic energy per unit volume.

Answer: d