Question

Structure of ammonia is:
A) Trigonal
B) Tetrahedral
C) Pyramidal
D)Trigonal pyramidal

Answer 1

Hint: The VSEPR theory helps in the prediction of the shape of molecules. This theory predicts shape on the basis of lone pairs and bond pairs surrounding the central atom. Here, we will use the VSEPR theory to identify ammonia's shape.

Complete Step by Step Answer:
Let's discuss the structure of ammonia. The ammonia is written by the formula of \[{\rm{N}}{{\rm{H}}_{\rm{3}}}\]. The nitrogen atom forms three bond pairs with the hydrogen atom. The count of valence electrons of the N atom in ammonia is five, and three electrons are used in the formation of covalent bonds with H atoms. And one lone pair is present.

Image: Structure of ammonia

Let's discuss the electron pair geometry of ammonia. As the molecule has three numbers of bond pairs and one lone pair, the electron pair geometry of ammonia is tetrahedral. As one lone pair and three numbers of bond pairs are present, the molecular shape of the ammonia molecule is trigonal bipyramidal.
Hence, option D is right.

Additional Information: Ammonia is a gas that has no colour. It possesses a distinct smell. It is a nitrogenous waste among aquatic organisms. It is an important component of many fertilisers. The pure form of ammonia can be directly applied to soil for fertility.

Note: If the electron pair geometry is tetrahedral, there are three possibilities, if no lone pair is present, then the shape of the molecule is tetrahedral. If one lone pair is present, the shape is trigonal bipyramidal (ammonia) and if two lone pairs are present, the shape is bent.