Question

8) A mixture of He, Ne and Ar has a pressure of 7.85 atm. If the Ne has a mole fraction of 0.47 and 8) Ar has a mole fraction of 0.23, what is the pressure of He? A) 4.2 atm B) 3.7 atm C) 5.5 atm D) 2.4 atm E) 1.8 atm

Answer 1

Answer: The correct answer is Option D.

Explanation:

To calculate the pressure of the Helium gas, we use the equation:

$p_i=\chi \times P$

where,

$p_i$ = partial pressure of the gas

$\chi$ = mole fraction of the gas

P = total pressure

We are given:

Sum of all the mole fraction is always equal to 1.

$\chi_{Ne}=0.47\\\chi_{Ar}=0.23\\\chi_{He}=(1-(0.47+0.23))=0.3\\P=7.85atm$

Putting values in above equation, we get:

$p_i=0.3\times 7.85=2.4atm$

Hence, the correct answer is Option D.