How many compounds given below are amphoteric oxides?
$P_2O_5, P_4O_6, As_2O_5, As_4O_6, Sb_2O_5, Sb_4O_6, Bi_2O_3$

Which among the group $15$ elements does $NOT$ exist as a tetra-atomic molecule?

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T$:
$\underline{P}Cl_3 + H_2O \longrightarrow H_3PO_3 + HCl$

The total number of paramagnetic gaseous products formed in all the following reactions $[A + B + C ]$:
$(A)\ NH_4 NO_3 \xrightarrow{\Delta} \text{Products}$
$(B)\ 3 NaNO_2 + 3 H_2 SO_4 \longrightarrow \text{Products}$
$(C)\ Pb(NO_3)_2 \xrightarrow{673 \ K} \text{Products}$

Concentrated $HNO_3$ turns brown on standing due to the formation of:

Which of the following compounds gives $N_2$ gas on thermal decomposition?