Question

why is NH3 soluble in H20 but NCl3 is not?

Answer 1

Cuz H-bond is formed in NH3 due to the presence of N but Cl is not soluble. Also Cl is a large atom so lone pair will be not easily available.

Answer 2

Inter-molecular hydrogen bonding of NH3 molecules and H2O molecules!!!

No such thing between NCl3 and H2O molecules, so this one's insoluble!

Answer 3

Condition for Hydrogen-bond :
1. H atom is attached to a highly electronegative atom (F, O or N)
2. Another molecule must contain an F, O or N atom that provides the lone pair of electrons

For NH3, since H atoms are attached to N, and O in a H2O molecule has 2 lone pairs of electrons. So, H-bond can be formed between NH3 and H2O. Thus, this NH3 is soluble in water.

For NCl3, since there is no H-atom attached to N, H-bond cannot be formed between H2O and NCl. So, NCl is not soluble in water.

Answer 4

The Hydrogen bonding present in both Ammonia and Water is what leads to their mutual solubility.
However, Water and NCl3 are different with respect to the strength of the forces holding the atoms together. In water, the bond is classified as polar(highly) due to the difference in the respective electronegativities of the Hydrogen and Oxygen atom. However, in NCl3, the forces keeping the Nitrogen and the Chlorines is not that strong due to the close electronegativity values since they are both nonmetals.
Therefore, differences in polarity between solute and solvent are what determine the extent of solubility.