The reaction of elemental $P_4$ and aqueous $NaOH$ gives

Which of the following does not give oxygen on heating?

Pure $N_2$ is obtained by:

The number of pentagons in $C_{60}$ and trigons (triangles) in white phosphorus,respectively,are

$A$ group $15$ element forms $d \pi - d \pi$ bond with transition metals. It also forms a hydride,which is the strongest base among the hydrides of other group members that form $d \pi - d \pi$ bonds. The atomic number of the element is $.......$

Phosphorous and phosphoric acids are, respectively, . . . . . . acids.