At T(K), equal weights of H₂, D₂, and T₂ are present in closed vessel. The pressure exerted by this gaseous mixture is P atm. The ratio of partial pressures of T₂, D₂ and H₂ is approximately
(H, D and T are isotopes of hydrogen).

$$\begin{gathered} {\mathrm{p}}_{\mathrm{total}}={\mathrm{p}}_{{\mathrm{H}}_2}+{\mathrm{p}}_{{\mathrm{D}}_2}+{\mathrm{p}}_{{\mathrm{T}}_2} \\ {\mathrm{p}}_{{\mathrm{H}}_2}=\mathrm{mole} \mathrm{fraction} \mathrm{of} {\mathrm{H}}_2\times {\mathrm{p}}_{\mathrm{total}} \\ \mathrm{mole} \mathrm{fraction} \mathrm{of} {\mathrm{H}}_2=\frac{\mathrm{number} \mathrm{of} \mathrm{moles} \mathrm{of} {\mathrm{H}}_2}{\mathrm{total} \mathrm{number} \mathrm{of} \mathrm{moles}} \\ {\mathrm{p}}_{{\mathrm{T}}_2}:{\mathrm{p}}_{{\mathrm{D}}_2}:{\mathrm{p}}_{{\mathrm{H}}_2} \\ \mathrm{mole} \mathrm{fraction} \mathrm{of} {\mathrm{T}}_2\times {\mathrm{p}}_{\mathrm{total}}:\mathrm{mole} \mathrm{fraction} \mathrm{of} {\mathrm{D}}_2\times {\mathrm{p}}_{\mathrm{total}}:\mathrm{mole} \mathrm{fraction} \mathrm{of} {\mathrm{H}}_2\times {\mathrm{p}}_{\mathrm{total}} \end{gathered}$$

Now weights are same for three gases:

$$\begin{gathered} \frac{{\displaystyle \frac{1}{6}}}{{\displaystyle \frac{1}{6}}+{\displaystyle \frac{1}{4}}+{\displaystyle \frac{1}{2}}}:\frac{{\displaystyle \frac{1}{4}}}{{\displaystyle \frac{1}{6}+\frac{1}{4}+\frac{1}{2}}}:\frac{{\displaystyle \frac{1}{2}}}{{\displaystyle \frac{1}{6}+\frac{1}{4}+\frac{1}{2}}} \\ 0.16:0.25:0.5 \end{gathered}$$