Question

In ammonia, a central nitrogen atom is bonded to three hydrogen atoms. Similarly, boron trifluoride has a central boron atom bonded to three fluorine atoms. However, ammonia is pyramidal and boron trifluoride is trigonal planar in shape. Which statement justifies this difference in their structure? The lone pair of electrons in boron trifluoride increases the bond angle between the bonding pairs, giving it a planar structure. The lone pair of electrons in boron trifluoride decreases the bond angle between the bonding pairs, giving it a planar structure. The lone pair of electrons in boron trifluoride stabilizes the bond angle between the bonding pairs, giving it a planar structure. The lone pair of electrons in ammonia increases the bond angle between the bonding pairs, giving it a pyramidal structure. The lone pair of electrons on the nitrogen in ammonia decreases the bond angle between the bonding pairs, giving it a pyramidal structure.

Answer 1

The answer to your question is The long pair of electrons on the nitrogen in ammonia decreases the bond angle between the bonding pairs , giving it a pyramid structure.

Answer 2

Answer: The lone pair of electrons on the nitrogen in ammonia decreases the bond angle between the bonding pairs, giving it a pyramidal structure.

Step-by-step explanation:

Formula used

`:{\text{Number of electrons}} =(1)/(2)[V+N-C+A]`

where, V = number of valence electrons present in central atom

N = number of monovalent atoms bonded to central atom

C = charge of cation

A = charge of anion

1.
`NH_3:`

`{\text{Number of electrons}} =(1)/(2)[5+3-0+0]=4`

The number of electrons is 4 that means the hybridization will be
`sp^3` and the electronic geometry of the molecule will be tetrahedral.

But as there are three atoms around the central carbon, the fourth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be trigonal pyramidal.

2.
`BF_3:`

`{\text{Number of electrons}} =(1)/(2)[3+3-0+0]=3`

The number of electrons is 3 that means the hybridization will be
`sp^2` and the electronic geometry of the molecule will be trigonal planar.