van der Waals' constants for neon and hydrogen are (${\mathrm{a}}_1, {\mathrm{b}}_1$) and (${\mathrm{a}}_2 , {\mathrm{b}}_2$ ) respectively. The maximum number of moles of neon which will form a homogeneous mixture with n2 moles of hydrogen at 25° C and constant pressure P is :

Gaseous mixtures are always homogeneous. So, maximum infinite number of moles can be added.Van der Waal's constants for neon and helium are as follows: neon: ${\mathrm{a}}_1, {\mathrm{b}}_1,$and helium: ${\mathrm{a}}_2, {\mathrm{b}}_2.$
because the gases can be blended together uniformly. These shouldn't be any specific ratio in order to allow for the mixing of indefinite moles.