Nitrous oxide $(N_2O)$ is........

Which of the following reactions correctly represent the products formed upon heating?
$(a) \ NH_4NO_2 \xrightarrow{\Delta } N_2 + 2H_2O$
$(b) \ NH_4NO_3 \xrightarrow{\Delta } N_2O + 2H_2O$
$(c) \ Na_2CO_3 \xrightarrow{\Delta } Na_2O + CO_2$
$(d) \ NH_4Cl \xrightarrow{\Delta } NH_3 + HCl$

Extra pure $N_2$ can be obtained by heating

The number of hydrogen atom$(s)$ attached directly to the phosphorus atom in hypophosphorous acid $(H_3PO_2)$ is:

What is the molecular formula of pyrophosphoric acid?

Which of the following statements is $NOT$ true for both white and red phosphorus?