All alkali metals dissolve in anhydrous liquid ammonia to give blue colour solution. It is the ammoniated electron which is reponsible for the blue colour of the solution, and the electrical conductivity is due to the ammoniated cation, `[M(NH_(3))_(x)]^(+)` as well as the ammoniated electron,` [e(NH_(3))_(y)]^(-)`, value of x and y depend on the extent of solvation by `NH_(3)`. Dilute solutions are paramagnetic due to free ammoniated electrons.
Q. Ammoniated solutions of alkali metals are reducing agents due to the presence of free ammoniated or solvated electrons that can reduce:
(I)`O_(2) "to" O_(2)^(2-)` (II) `K_(2)[Ni(CN)_(4)] " to "K_(4)[Ni(CN)_(4)]`
(III) Aromatic ring (IV) Non-terminal alkyne
Choose the correct code:

Options

A. III and IV
B. II and III
C. I, II, III and IV
D. I, III and IV

Answer

C

Explanation

`M(s)+underset("excess")(NH_(2))(l) to M^(+)(NH_(3)_(2)+overline(e)(NH_(3))_(2)`
ammoniated `overline(e)` responsible for blue colour and reducing character.
If conc. Of solution is increased, then associated of solvated electrons gas started hence, paramagnetism decrease and solution changes to bronze colour.