Question

When moderate amount of sodium metal is dissolved in liquid $N{H}_3$ at low temperature, which one of the following occur(s) ?

• A. Blue colored solution is obtained.
• B. $N{a}^{+}$ ions are formed in the solution.
• C. Liquid $N{H}_3$ becomes good conductor of electricity.
• D. Liquid $N{H}_3$ remains diamagnetic.

Answer 1

Answer: (A), (B), (C)

The correct options are
A $N{a}^{+}$ ions are formed in the solution.
B Blue colored solution is obtained.
C Liquid $N{H}_3$ becomes good conductor of electricity.

A small piece of sodium is cut to expose a fresh surface. The sodium is dropped into liquid ammonia at a temperature of approximately $-{33}^{0}C$. Some sodium dissolves, forming sodium cations surrounded by ammonia molecules and electrons surrounded by ammonia molecules.

The solvated electrons give the blue color to the solution.Because of the mobility of the electrons, the solution is a good electrical conductor. Bubbles of hydrogen gas are formed by a second reaction that also produces sodium amide. More concentrated solutions appear bronze-colored and have a conductivity similar to metals.

$2Na+2N{H}_3\to 2NaN{H}_2+H_2$.

Hence options A,B & C are correct.