Question

How would you balance $ {H_2} + {O_2} = {H_2}O $ ?

Answer 1

Hint: We need to balance the chemical reaction for the formation of water. We can only change the coefficients during balancing. A balanced chemical reaction has equal number of each element in the reactant and product side, according to the law of constant proportion and conservation of mass.

Complete step by step answer
We already know that water is formed by $ {H_2}{\text{ and }}{O_2} $ .
We have the equation given as:
 $ {H_2} + {O_2} = {H_2}O $
The above reaction has to be balanced.
When balancing chemical equations, we should be aware of having the same number of each type of atom on both sides of the equation. Only change the coefficients (these are the numbers in front substances). We shall balance the number of oxygen in the products side and then, adjust the hydrogen in the reactants side.
 $ 2{H_2} + {O_2} \to 2{H_2}O $
Thus, the above reaction is balanced.

Note
Water, a substance composed of the chemical elements hydrogen and oxygen and existing in gaseous, liquid, and solid states. It is one of the most plentiful and essential of compounds. A tasteless and odourless liquid at room temperature, it has the important ability to dissolve many other substances.
The water molecule is composed of two hydrogen atoms, each linked by a single chemical bond to an oxygen atom. Most hydrogen atoms have a nucleus consisting solely of a proton. Two isotopic forms, deuterium and tritium, in which the atomic nuclei also contain one and two neutrons, respectively, are found to a small degree in water. Deuterium oxide $ \left( {{D_2}O} \right) $ , called heavy water, is important in chemical research and is also used as a neutron moderator in some nuclear reactors. The water molecule is not linear but bent in a special way. The two hydrogen atoms are bound to the oxygen atom at an angle of $ {104.5^0} $ .
Hydrogen atoms in water molecules are attracted to regions of high electron density and can form weak linkages, called hydrogen bonds, with those regions. This means that the hydrogen atoms in one water molecule are attracted to the nonbonding electron pairs of the oxygen atom on an adjacent water molecule.