Question

Assertion : Effusion rate of oxygen is smaller than nitrogen.
Reason : Molecular size of nitrogen is smaller than oxygen.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

Rate of effusion $\propto \frac{1}{\sqrt{M}}$
$[M=$ Molecular mass $]$
as molecular mass of $O_2=32g$
molecular mass of $N_2=28g$
molecular mass of $O_2$ is more than $N_2$
$\therefore$ rate of effusion of $O_2$ is less than that of $N_2$
$\because r\propto \frac{1}{\sqrt{m}}$
Molecular size of nitrogen is greater than oxygen as size decrease in a period from left to right