Chemistry - CHEMICAL BONDING Question with Solution | TestHub
The bond angles in NH3, NF3and NCl3are in the order :
Options:
Answer:
Solution:
Comparison of NH3and NF3: Since N is more electronegative than hydrogen, shared pair of electrons of the N - H bond spent more time with nitrogen ( closer to nitrogen) giving a greater bond pair repulsion. On the other hand fluorine is more electronegative than nitrogen, shared pair of electrons of N - F bond spent more times with fluorine ( closer to fluorine ) giving less bond pair repulsion as compared to N - H bond. Although bond pair bond pair repulsion in both cases are less than lone pair - bond repulsion, contraction in bond angle is more in NF3due to smaller bond pair repulsion in this case than in NH3. Hence bond angles are less than 109028' in both cases but it is further less in NF3
Comparison of NH3and NCl3: In NCl3, chlorine is much larger in size than hydrogen, they comes closer and their valence shell electrons start repelling one another. Therefore, in NCl3the bond expand to some extent to compensate this repulsion:
Significant repulsion between the valence electrons of chlorine atom overcomes the lone pair bond - pair repulsion .
Hence, the overall order of bond angle is
NCl3> NH3> NF3