The nitrate of which of the following metals does mot liberate $\mathrm{NO}_2$ gas on heating?

What are the correct statements about the elements of group 13 given below?

(I) The stability of +1 oxidation state follows the order $\mathrm{Tl}>\mathrm{In}>\mathrm{Ga}$.

(II) Boron has the lowest melting point and boiling point as it is a non-metal.

(III) Boron shows a maximum covalency of 4 in its compounds.

(IV) The order of atomic radius is $\mathrm{Ga}>\mathrm{Al}>\mathrm{In}$.

(V) Aluminium is passive to concentrated nitric acid.

Consider the reaction,

$$ \mathrm{P}_4+3 \mathrm{NaOH}+3 \mathrm{H}_2 \mathrm{O} \longrightarrow Q+3 \mathrm{NaH}_2 \mathrm{PO}_2 $$

Identify the reaction in which $Q$ is not the product. (equations are not balanced)

The oxidation state of sulphur atoms and numbers of $\mathrm{S}-\mathrm{OH}$ bonds in peroxydisulphuric acid are respectively