Equal masses of helium and oxygen are mixed in an empty container at $25^{\circ} \mathrm{C}$. What is the fraction of the total pressure exerted by helium?

A container contains $4 \mathrm{~g} \mathrm{H}_2, 4 \mathrm{~g} \mathrm{He}$ and certain amount of 'Ne' at a certain temperature. What is the mass of 'Ne' required so that the partial pressure exerted by 'Ne' is equal to the partial pressure of He ?

A container contains equal masses of $\mathrm{H}_2, \mathrm{He}$, $\mathrm{CO}_2$ and Ne at a certain temperature. Which of the following gases exerts minimum partial pressure?

A container contains equal masses of $\mathrm{H}_2, \mathrm{He}$, $\mathrm{CO}_2$ and Ne at a certain temperature. Which of the following gas exerts maximum partial pressure?