Question

What is the action of the sodium metal in ammonia?
A) Ammonia gas is released
B) Hydrogen gas is released
C) Oxygen gas is released
D) Nitrogen gas is released

Answer 1

Hint: Sodium metal is a highly reactive metal. Ammonia is highly stable to heat and light but highly reactive with oxidizing gases. The type of reaction is displacement reaction.

Complete step by step solution:
-Sodium is an alkali metal which is highly reactive when comes in contact with water or air. Hence it is kept by immersing in kerosene. But it acts as a strong base when it reacts with water and forms sodium hydroxide $(NaOH)$.
-Ammonia is a base which reacts violently with acids. Highly reactive towards the reducing agents and it reacts with silver and mercury explosively to form its compounds.
 -Sodium and ammonia react in the room temperature in a slow reactivity range to produce amide (sodium amide), with the liberation of hydrogen.
\[2Na+2N{{H}_{3}}\to 2NaN{{H}_{2}}+{{H}_{2}}\]

- The reaction involving sodium and ammonia which results in formation of sodium amide and hydrogen can be accelerated by adding many metal oxides or metal.
-This reaction can be considered as a displacement reaction as in this reaction a hydrogen is replaced from the ammonia with sodium and forms the sodium amide with the evolution of hydrogen.
So, the correct answer is “Option B”.

Additional Information:
Liquid ammonia is an effective solvent that dissolves sodium metal and carries out many reactions at the room temperature that requires intense heat. Best example is that of the formation of sodium superoxide ($Na{{O}_{2}}$) by passing oxygen through the sodium-ammonia solution. The sodium-ammonia solution is a very good reducing agent and due to its reducing nature it finds application in many organic reactions like Birch reduction.
So, the correct answer is “Option B”.

Note: Sodium like other alkali metals reacts with the liquid ammonia to produce deep blue colour solution. The blue solution of the sodium metal in ammonia is due to the formation of ammoniated electrons and ammoniated cations in the solution. The solution is paramagnetic in nature and its colour increases as the concentration of sodium metal increases blue solution changes to bronze colour solution.