The pressure of a 1: 4 mixture of dihydrogen and dioxygen enclosed in a vessel is one atmosphere. What would be the partial pressure of dioxygen?

Given that, pressure of a 1 : 4 mixture of H₂ and O₂ enclosed in a vessel is one atmosphere. This suggests that the moles ratio of H₂ and O₂ is 1:4. Thus, partial pressure of dioxygen (O₂ ) is given as

$\therefore \text{ Partial pressure of }{\mathrm{O}}_2=\text{ mole fraction of }{\mathrm{O}}_2\times \text{ total pressure of mixrure}$

$$\begin{gathered} =\frac{4}{1+4}\times 1=\frac{4}{5}\times 1\mathrm{atm}=0.8\mathrm{atm}=0.8\times {10}^5 \\ {\mathrm{Nm}}^{-2}=8\times {10}^4{\mathrm{Nm}}^{-2} \end{gathered}$$