Question 68: Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R :
Assertion A : Metallic sodium dissolves in liquid ammonia giving a deep blue solution, which is paramagnetic.
Reasons R : The deep blue solution is due to the formation of amide.
In the light of the above statements, choose the correct answer from the options given below :
(1) \mathbf{A} is true but \mathbf{R} is false.
(2) \mathbf{A} is false but \mathbf{R} is true.
(3) Both \mathbf{A} and \mathbf{R} are true and \mathbf{R} is the correct explanation of \mathbf{A}.
(4) Both \mathbf{A} and \mathbf{R} are true but \mathbf{R} is NOT the correct explanation of \mathbf{A}.
Answer: Option (1)
Explanation:
When metallic sodium dissolves in liquid ammonia, it forms a deep blue solution containing solvated electrons.
These solvated electrons are responsible for the blue colour and the paramagnetic nature of the solution.
The formation of sodium amide occurs only on prolonged standing or in the presence of a catalyst and does not cause the blue colour.
Hence, Assertion A is true, but Reason R is false.