Potassium nitrate is called

The blue colour of the solution (metal dissolved in liquid ammonia) is due to

Which among the following alkali metal elements is used as a coolant in fast breeder nuclear reactors?

Correct order of solubility is

Starting with sodium chloride,how would you proceed to prepare:
$(i)$ sodium metal
$(ii)$ sodium hydroxide
$(iii)$ sodium peroxide
$(iv)$ sodium carbonate?

Which metal gives $NH_4NO_3$ when it reacts with very dilute $HNO_3$ acid?