Question

A mixture of dihydrogen and dioxygen at one bar pressure contains 20% by weight of dihydrogen. Calculate the partial pressure of dihydrogen.

• A. 0.8 bar
• B. 0.4 bar
• C. 1.6 bar
• D. 3.2 bar

Answer 1

Answer: (A)

Let the weight of mixture $=100g$
Mole $=\frac{\text{ Given weight }}{\text{ Molecular weight }}$
Weight of dihydrogen $=20g$
Moles of dihydrogen $=10$
Weight of dioxygen $=80g$
Moles of dioxygen $=5$
$P_{H_2}=P_{\text{Total }}\cdot X_{H_2}$
$=P_{\text{Total }}\times \frac{n_{H_2}}{n_{H_2}+n_{O_2}}$
$=1\times \frac{\frac{20}{2}}{\frac{20}{2}+\frac{80}{32}}\text{ bar }=0.8\mathrm{bar}(\text{ approximately })$