Q.Explain the following:
Sodium dissolves in liquid ammonia to form a solution which shows electrical conductivity.

The blue colour of alkali metals dissolved in liquid ammonia comes from free electrons trapped and stabilised by surrounding NH3 molecules (ammoniated electrons).

When an alkali metal M is dissolved in liquid ammonia, it ionises as:

M + (x+y) NH3 → [M(NH3)x]+ + [e(NH3)y]−

The metal loses its valence electron, which does not immediately combine with another species but instead gets trapped in a cavity formed by surrounding ammonia molecules — this is called a solvated or ammoniated electron. These loosely held, mobile electrons can absorb energy corresponding to wavelengths in the visible region of the spectrum (specifically at the red/near-infrared end), and this selective absorption of light is what gives dilute solutions their characteristic deep blue colour. (At higher, more concen …