The geometry of ammonia molecule is

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ATrigonal pyramidal

BTrigonal planar

CTetrahedral

DLinear

Answer:

The ammonia molecule, with the chemical formula NH₃, exhibits a trigonal pyramidal geometry.
This shape arises due to the arrangement of atoms and the presence of a lone pair of electrons on the central nitrogen atom.

According to VSEPR theory, electron pairs (both bonding and lone pairs) around the central atom repel each other and arrange themselves to minimize this repulsion.
In ammonia, the central nitrogen atom is bonded to three hydrogen atoms and possesses one lone pair of electrons.
This gives a total of four electron domains (three bonding pairs and one lone pair) around the nitrogen atom.
These four electron domains arrange themselves in a tetrahedral electron geometry to maximize the distance between them.

While the electron domains adopt a tetrahedral arrangement, the molecular geometry is determined only by the positions of the atoms.
The lone pair occupies space and exerts a stronger repulsive force than bonding pairs, pushing the N-H bonds closer together.
This distortion from a perfect tetrahedron results in the characteristic trigonal pyramidal shape of the ammonia molecule.
The three hydrogen atoms form the base of the pyramid, and the nitrogen atom is at the apex.

In an ideal tetrahedral geometry, the bond angles would be approximately 109.5 degrees.
However, due to the greater repulsion from the lone pair, the H-N-H bond angles in ammonia are slightly compressed to about 107 degrees.

The central nitrogen atom in ammonia is sp³ hybridized.
This hybridization involves the mixing of one 2s orbital and three 2p orbitals to form four equivalent sp³ hybrid orbitals.
Three of these sp³ hybrid orbitals overlap with the 1s orbitals of the hydrogen atoms to form sigma bonds.
The fourth sp³ hybrid orbital contains the lone pair of electrons.

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