Question

Catalyzed by iron, alkali metals dissolve in liquid ammonia to yield:

• A. Metal amide
• B. $Fe.(N{H}_4{)}^x$
• C. $H_2$
• D. Iron hydride

Answer 1

Answer: (A), (C)

$H_2$

Let $M$ be any alkali metal

$M\to M^{+}+e^{-}$

$M^{+}+xN{H}_3\to \left[M\right(N{H}_3{)}_x{]}^{+}$

$e^{-}+yN{H}_3\to \left[e\right(N{H}_3{)}_y{]}^{+}$

$M+(x=+y)N{H}_3\to \left[e\right(N{H}_3{)}_y{]}^{+}+\left[M\right(N{H}_3{)}_x{]}^{+}$

When the above reactions are catalyzed by Iron oxide or platinum black, the solution decomposes into $H_2$ and metal amide

$Na+N{H}_3\to NaN{H}_2+\frac{1}{2}{H}_2$