Question

Which is most likely an example of an angular molecule? NH3 H2O SiCl4 H2CO

Answer 1

Answer : The correct option is, $H_2O$

Explanation :

Formula used  :

$\text{Number of electron pair}=\frac{1}{2}[V+N-C+A]$

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

Now we have to determine the hybridization of the following molecules.

(1) The given molecule is, $NH_3$

$\text{Number of electrons}=\frac{1}{2}\times [5+3]=4$

The number of electron pair are 4 that means the hybridization will be $sp^3$ and the electronic geometry of the molecule will be tetrahedral.

But as there are 3 atoms around the central nitrogen atom, 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) The given molecule is, $H_2O$

$\text{Number of electrons}=\frac{1}{2}\times [6+2]=4$

The number of electron pair are 4 that means the hybridization will be $sp^3$ and the electronic geometry of the molecule will be tetrahedral.

But as there are 2 atoms around the central oxygen atom, the third and 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 bent or angular.

(3) The given molecule is, $SiCl_4$

$\text{Number of electrons}=\frac{1}{2}\times [4+4]=4$

The number of electron pair are 4 that means the hybridization will be $sp^3$ and the electronic geometry of the molecule will be tetraheadral.

(4) The given molecule is, $H_2CO$

$\text{Number of electrons}=\frac{1}{2}\times [4+2]=3$

The number of electron pair are 4 that means the hybridization will be $sp^2$ and the electronic geometry of the molecule will be trigonal planar.

Hence, the correct option is, $H_2O$

Answer 2

The best option is B H2O.
A molecule of water has an angular or bent shape. The H-O-H bond angle in a molecule of water is 104.5.