Suppose you carry out the following reaction of ammonia and boron trifluoride in the laboratory.

(a) What is the geometry of the boron atom in BF₃? In H₃N→BF₃?

(b) What is the hybridization of the boron atom in the two compounds?

(c) Considering the structures and bonding of NH₃ and BF₃, why do you expect the nitrogen on NH₃ to donate an electron pair to the B atom of BF₃?

(d) BF₃ also reacts readily with water. Based on the ammonia reaction above, speculate on how water can interact with BF₃.

Interpretation:

The geometry of boron atom in BF3  and  in H3N→BF3 should be determined.

Concept Introduction

Hybridization is the mixing of valence atomic orbitals to get equivalent hybridized orbitals that having similar characteristics and energy.

Geometry of a molecule can be predicted by knowing its hybridization.

Type  of moleculeHybridaization      Atomic  orbitals used for hybridaization GeometryAX2sp1s+1pLinearAX3,AX2Bsp21s+2pTrigonal planarAX4,AX3B,AX2B2sp31s+3pTetrahedralAX5,AX4B,AX3B2,AX2B3sp3d1s+3p+1dTrigonal  bipyramidalAX6,AX5B,AX4B2sp3d21s+3p+2dOctahedralA → Central  atomX → Atoms  bonded  to  AB  → Non bonding electron pairs  on  A

Given reaction of ammonia and boron trifluoride is,

Due to the presence of three electron pairs around the central boron atom in BF3 molecule, it has trigonal planar structure

Interpretation:

The hybridization of boron atom in BF3  and  in H3N→BF3 should be determined.

Concept Introduction

Hybridization is the mixing of valence atomic orbitals to get equivalent hybridized orbitals that having similar characteristics and energy.

Geometry of a molecule can be predicted by knowing its hybridization.

Type  of moleculeHybridaization      Atomic  orbitals used for hybridaization GeometryAX2sp1s+1pLinearAX3,AX2Bsp21s+2pTrigonal planarAX4,AX3B,AX2B2sp31s+3pTetrahedralAX5,AX4B,AX3B2,AX2B3sp3d1s+3p+1dTrigonal  bipyramidalAX6,AX5B,AX4B2sp3d21s+3p+2dOctahedralA → Central  atomX → Atoms  bonded  to  AB  → Non bonding electron pairs  on  A

Interpretation:

The nitrogen on NH3 donate an electron pair to the Boron atom of BF3. The correct reason behind this should be explained.

Concept Introduction:

Lewis structures are diagrams that represent the chemical bonding of covalently bonded molecules and coordination compounds.

It is also known as Lewis dot structures which represent the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule.

The Lewis structure is based on the concept of the octet rule so that the electrons shared in each atom should have 8 electrons in its outer shell.

According to Lewis concept, acid is an electron acceptor and base is an electron donor.

Interpretation:

Speculate on how water can interact with BF3 like the NH3 reacts with BF3.

Concept Introduction:

Lewis structures are diagrams that represent the chemical bonding of covalently bonded molecules and coordination compounds.

It is also known as Lewis dot structures which represent the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule.

The Lewis structure is based on the concept of the octet rule so that the electrons shared in each atom should have 8 electrons in its outer shell.

According to Lewis concept, acid is an electron acceptor and base is an electron donor.