Question

What is full form of H2O?

Answer 1

Here,

H₂  indicates Hydrogen

O  indicates oxygen.

Full form of H₂O is

Two atoms of hydrogen combines with One atom of Oxygen to form one molecule of  Water.

H₂O is the chemical formula indicating the reaction of formation of water molecules.

These two atoms are join together by  forming covalent bonds among themselves.

Answer 2

$\bold{H_2O}$ is used to denote water, is chemical representation of water.

Explanation:

Water is a compound of oxygen and hydrogen. The chemical formula generally represents the number of atoms present in a compound. Thus, in one water molecule, there are two hydrogen and one oxygen atoms.  

Water is a tasteless and colorless compound. The solid form of water is ice and gas form of water is water vapor. 70% of earth surface has water.