Give the uses of $LiBH_4$ and $NaBH_4$.

Identify the correct statements from the following.
$(i)$ The number of hydrogen bonded water molecules in copper sulphate pentahydrate is one.
$(ii)$ Lanthanum and zirconium form non-stoichiometric hydrides.
$(iii)$ In solid form of $H_2O$, each oxygen is surrounded by six oxygen in octahedral positions at a distance of $276 \ pm$.

Which of the following is not a type of laser?

Calorific value of producer gas is low because of

The charring of sugar,when treated with conc. $H_2SO_4$,is due to

On reaction with $Mg$,very dilute nitric acid produces