Question

$200ml$ of $He$ at $0.66atm$ pressure and $400ml$ of $O_2$ at $0.52atm$ pressure are mixed in a $400ml$ vessel at ${25}^{\circ }C$. The partial pressure of $He$ and $O_2$ will be:

• A. $0.33and0.56$
• B. $0.33and0.52$
• C. $0.38and0.56$
• D. $0.25and0.45$

Answer 1

Answer: (B)

$0.33and0.52$

Partial pressure is the pressure of individual gas when it is placed in a required vessel or in final vessel.

Given :- Initially volume of $He$ is $200ml$ at $0.66atm$ after placing it in a vessel of volume $400ml$

$P_1{V}_1=P_2{V}_2$

$.66\times 200=P_2\times 400$

$P_2=0.33atm$ ----------- (Partial pressure of $He$)

Initially $O_2$ is present at $0.25atm$ in $400ml$ volume and then it is placed in $400ml$ vessel hence the partial pressure of $O_2$ is $0.52atm$

Partial pressure of $He=0.33atm$

Partial pressure of $O_2=0.52atm$