Question

A gaseous mixture at temperature T(K) consists of dihydrogen and dioxygen, with a total pressure of 2 2 bar. If the mixture is 33.33% dihydrogen and 66.67% dioxygen, what is the approximate partial pressure (in bar) of dihydrogen? (T(K), 2 bar total pressure)

• A. 1.778
• B. 0.222
• C. 1.5
• D. 0.5

Hint:

To find the partial pressure, multiply the mole fraction of the gas by the total pressure. Convert percentages to decimals first.

Answer 1

The Correct Option is D

The total pressure of the mixture is 2 bar. The mole fraction of dihydrogen is 33.33% = $\frac{33.33}{100} \approx 0.3333$. 
Partial pressure of dihydrogen = mole fraction $\times$ total pressure = $0.3333 \times 2 = 0.6666 \approx 0.67$ bar. 
The closest option to 0.67 bar is 0.5, so the approximate partial pressure of dihydrogen is 0.5 bar.