The element from group 15 that forms a strong bond with hydrogen is:

PH₃ forms bubbles when passed slowly through water but NH₃ gets dissolved in water, because: 

The bonding present in nitrogen molecules is:
1. \(p\pi-p\pi\)
2. \(p\pi-d\pi\)
3. \(d\pi-d\pi\)
4. Only sigma bond

An element that does not have a d-orbital is:

NH₃ forms a hydrogen bond but PH₃ does not because:  

A balanced chemical equation for the reaction showing catalytic oxidation of NH₃ by atmospheric oxygen is:

An element belongs to group 15 and 3^rd period of the periodic table. Its electronic configuration would be:
1. \(\mathrm{1 s^2 2 s^2 2 p^4} \)
2. \(\mathrm{1 s^2 2 s^2 2 p^3} \)
3. \(\mathrm{1 s^2 2 s^2 2 p^6 3 s^2 3 p^2} \)
4. \(\mathrm{1 s^2 2 s^2 2 p^6 3 s^2 3 p^3}\)

Nitrogen gas is liberated by the thermal decomposition of:

1. ${\mathrm{NH}}_4{\mathrm{NO}}_2$                                 

2. ${\mathrm{NaN}}_3$

3. ${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$                           

4. All of the above. 

The correct structure of pyrophosphoric acid is:

1.		2.
3.		4.

Ammonium dichromate and barium azide on heating gives: