Question

On the basis of VSEPR theory predict the shape of Hydronium (H3O+ ) ion.

Answer 1

VBT explains molecular shapes with the help of hybrization. In H3O+, the central atom ( oxygen ) has three bond pairs and one lone pair and hence, it is sp3 hybridized. You must be knowing that ideal geometry for a sp3 hybridized central atom molecule is Tetrahedral. ... It is the Lewis structure of the hydronium ion.

Answer 2

Answer: Hence the hybridisation in the central atom of $H_3O^+$ is $sp^3$ and electronic geometry is trigonal pyramidal.

Explanation:

Formula used  :

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

where,

V = number of valence electrons present in central atom  = 6

N = number of monovalent atoms bonded to central atom  = 3

C = charge of cation  = +1

A = charge of anion  = 0

Now we have to determine the hybridization of the $H_3O^+$  molecules.

$\text{Number of electrons}=\frac{1}{2}\times [6+3-1]=4$

Bond pair electrons = 3

Lone pair electrons = 4 - 3 = 1

The number of electrons are 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 oxygen 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.

Hence, the hybridisation in the central atom is $sp^3$ and geometry is trigonal pyramidal.

Hence the hybridisation in the central atom of $H_3O^+$ is $sp^3$ and geometry is trigonal pyramidal.