Question

Balance the equation: Hydrogen Sulfide gas burns in the air to give Water and Sulfur dioxide.

Answer 1

Balanced chemical equation:

1. Balancing chemical equation refers to balancing the stoichiometric coefficients on the reactants and products side.
2. This must be done as the chemical equation obeys the law of conservation of mass and momentum.

The equation for the reaction burning of Hydrogen sulfide gas in the air to give water and sulfur dioxide:

${\mathrm{H}}_2\mathrm{S}\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+{\mathrm{SO}}_2\left(\mathrm{g}\right)$

Following are the easy steps to balance the equation:

Step 1:

Write the unbalanced chemical equation.

Let us consider the given reaction.

That is the reaction between Hydrogen sulfide gas burns in air to give water and sulfur dioxide.

${\mathrm{H}}_2\mathrm{S}+{\mathrm{O}}_2\to {\mathrm{SO}}_2+{\mathrm{H}}_2\mathrm{O}$

Step 2:

Write down the number of atoms

Write down the number of atoms of each element present on both the reactant and product side

Atom	Reactant side	Product side
H	1	2
S	1	1
O	2	3

Step 3:

Add coefficients to balance the mass in a chemical equation

Note that the coefficients that are to be added must be a whole number and one coefficient added applies to all the atoms present in that one particular molecule.

Example

$2{\mathrm{H}}_2\mathrm{O}$ implies 4 hydrogen atoms and 2 oxygen atoms.

First try to balance the single element oxygen atom and then move to hydrogen

So here we will first balance sulfur and then oxygen

Go by trial and error method.

Adding 2 Hydrogen on both sides then it will be 4 on the reactants side and on the product side 4.

So 2 H works, 2 hydrogen sulfide, making it $2{\mathrm{H}}_2\mathrm{O}$

The same trial and error procedure is now followed to balance oxygen

$3{\mathrm{O}}_2$ then we have 6 oxygen atoms on the reactant side and also 6 oxygen atoms on the product side.

Hence, The balanced chemical equation is:

$2{\mathrm{H}}_2\mathrm{S}+3{\mathrm{O}}_2\to 2{\mathrm{SO}}_2+2{\mathrm{H}}_2\mathrm{O}$

Rewriting in the table for verification:

Upon putting the values in the table we get,

Atom	Reactant side	Product side
H	4	4
S	2	2
O	6	6

Now the atoms are balanced in both reactant and on the product side.

Hence, the balanced chemical equation for Hydrogen sulfide gas burns in air to give water and sulfur dioxide is given as

$2{\mathrm{H}}_2\mathrm{S}+3{\mathrm{O}}_2\to 2{\mathrm{SO}}_2+2{\mathrm{H}}_2\mathrm{O}$