Assertion (A) Helium has lowest boiling point (4.2 K).
Reason (R ) The forces that exist between helium atoms are weak disperson forces.

Options

A. Both (A) and (R ) are correct and (R ) is the correct explanation of (A)
B. Both (A) and (R ) are correct but (R ) is not the correct explanation of (A)
C. (A) is correct but (R ) is false.
D. A is incorrect but (R ) is correct

Answer

A

Explanation

Helium has lowest boiling point (4.2 K) because the forces of attraction between He atoms are weak dispersion forces.
Thus, both assertion and reason are correct and reason (R ) is the correct explanation of assertion (A).