Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: $$PH_3$$ has lower boiling point than $$NH_3$$. Reason R: In liquid state $$NH_3$$ molecules are associated through Vander Waal's forces, but $$PH_3$$ molecules are associated through hydrogen bonding. In the light of the above statements, choose the most appropriate answer from the options given below:

The Assertion A states that $$PH_3$$ has a lower boiling point than $$NH_3$$. This statement is correct because boiling point depends on the strength of intermolecular forces. Ammonia ( $$NH_3$$ ) molecules exhibit hydrogen bonding, which is a stronger intermolecular force compared to the van der Waals forces present in phosphine ( $$PH_3$$ ).

The Reason R states that in the liquid state $$NH_3$$ molecules are associated through van der Waals forces, but $$PH_3$$ molecules are associated through hydrogen bonding. This statement is incorrect. In fact, $$NH_3$$ molecules form hydrogen bonds due to the high electronegativity of nitrogen and the presence of lone pair on nitrogen. On the other hand, $$PH_3$$ molecules cannot form hydrogen bonds because phosphorus is less electronegative and its lone pair is less available for hydrogen bonding; thus, $$PH_3$$ molecules are held together primarily by weaker van der Waals forces.

Since Assertion A is correct and Reason R is not correct, the correct choice is Option D: A is correct but R is not correct.