99 Percentile Qs Bank for JEE MainChemistryp Block Elements (Group 15, 16, 17 & 18)
Bond angle in P H 3 is closer to 90 ° while that in N H 3 is 104.5 ° . Which of the following best explains this structural feature?
Options
- ADue to larger size of the lone pair electron cloud, there is larger lone pair – bond pair repulsion in P H 3 c
- BHigher electronegativity of nitrogen concentrates the bond pair electron cloud near the central atom which inc
- CEnergy difference between 3 s and 3 p orbitals is quite high and hence the lone pair on phosphorous prefers to
- DPhosphorous forms p π - d π bonds while nitrogen does not.
Correct answer
C. Energy difference between 3 s and 3 p orbitals is quite high and hence the lone pair on phosphorous prefers to
Step-by-step solution
In the hydrides of group 15 and group 16 (except N H 3 and H 2 O ) the energy difference between 3 s and 3 p orbital’s is quite high. Hybridization increases the energy of 3 s orbital so much that lone pair rather prefers to occupy unhybridized s orbital. For example, in P H 3 , 600 k J m o l - 1 of energy is required to hybridize the central atom. So, to avoid such energy demanding hybridization P forms bonds with unhybridized p orbitals leaving the lone pair in the spherical s orbital which leads to a bond angle