1. NF3 has no tendency to act as a ligand. why ?

ans - bcoz the dipole moment due to 3 N-F bonds  is in opposite direction to that due to the lone pair of electrons on N . thus it doesn't act as a ligand as lone pair of electron on nitrogen is not freely available.

 

2. on being slowly passed through water PH3 forms bubbles but NH3 dissolves. why ?

ans- NH3 forms H-bonds with water and dissolves. but PH3 doesn't and escapes out.

 

3. Ammonia is used as a refrigerant and in ice factories .why?

ans- presence of strong H-bonding in liquified NH3 , it has very very large latent heat of vapourization and remains in the liquid state as it doesn't vapourize easily.

 

4. NO is paramagnetic in gaseous state  but diamagnetic in liq. and solid states . why ?

ans - NO has odd number of electrons (15)  in the gaseous state .but in the solid and liq .  states , it forms a dimer and doesn't contain unpaired electrons.