Question

A mixture contains 16 g of oxygen ,28g of nitrogen and 8g of methane.Total pressure of the mixture is 740mm. What is the partial pressure of nitrogen in mm?

• A. 185
• B. 370
• C. 555
• D. 740

Answer 1

The correct option is B 370

As no of moles of $O_2=16/32=0.5$ moles

no of moles of $N_2=28/28=1$ moles

no of moles of $C{H}_4=8/16=0.5$ moles

Total pressure=740mm

Partial pressure=total pressure$\times$ mole fraction of $N_2$

Mole fraction of $N_2$ = No of moles of $N_2$ /total no of moles

$=1/0.5+0.5+1=1/2$

then partial pressure $=1/2\times 740$

$=370mm$