Assertion (A) At critical temperature, surface tension of liquids become zero. Reason (R) At critical…
Assertion (A) At critical temperature, surface tension of liquids become zero.
Reason (R) At critical temperature, intermolecular forces for liquids and gases become equal.
Both $\mathrm{A}$ and $\mathrm{R}$ are true and $\mathrm{R}$ is a correct explanation for $A$.
Both $A$ and $R$ are true but $R$ is not a correct explanation for $\mathrm{A}$.
$A$ is true but $R$ is false.
$A$ is false but $R$ is true.
Solution
Critical temperature is temperature at which surface tension of liquid become zero. So it is true. At critical temperature, the intermolecular force between liquid molecules become very weak due to which interaction between molecules vanishes.
Hence, surface tension reduces. So, Reason (R) is also true and is a correct explanation for Assertion (A).