Which one of the following group-\( 15 \) hydride is the strongest reducing agent?
Among the following oxides of p-block elements, number of oxides having amphoteric nature is ______.
\( \mathrm{Cl_2O_7} \), \( \mathrm{CO} \), \( \mathrm{PbO_2} \), \( \mathrm{N_2O} \), \( \mathrm{NO} \), \( \mathrm{Al_2O_3} \), \( \mathrm{SiO_2} \), \( \mathrm{N_2O_5} \), \( \mathrm{SnO_2} \)
