$\mathrm{Zn}+\mathrm{HCl}\to {\mathrm{ZnCl}}_2+{\mathrm{H}}_2$

How many Zinc atoms are there in the reactant side and in the product side? Which are the atoms showing a difference in their number?

In order to make equal number of atoms on both sides how many molecules of $\mathrm{HCI}$ should be taken as reactant.

$\mathrm{Zn}+\mathrm{HCl}\to {\mathrm{ZnCl}}_2+{\mathrm{H}}_2$

$2\mathrm{Al}+3{\mathrm{O}}_2\to 2{\mathrm{Al}}_2{\mathrm{O}}_3$

Is the number of aluminium atoms equal on both the sides? If not, how can we make it equal and state whether it is a balanced chemical equation?

Some chemical equations are given below. Note down the number of reactant atoms and that of product atoms in the table given below.

1. $\mathrm{C}+{\mathrm{O}}_2\to {\mathrm{CO}}_2$
2. ${\mathrm{N}}_2+{\mathrm{H}}_2\to {\mathrm{NH}}_3$
3. $2{\mathrm{H}}_2{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$
4. ${\mathrm{SO}}_{2 }+{\mathrm{O}}_2\to {\mathrm{SO}}_3$
5. ${\mathrm{BaCl}}_2+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{BaSO}}_4+2\mathrm{HCl}$

Balance the equations which are unbalanced.

How many electrons are accepted by each chlorine atom? What will be the charge acquired by each atom?

$\mathrm{Mg}+{\mathrm{Cl}}_2\to {\mathrm{MgCl}}_2$

$\mathrm{Mg}+{\mathrm{Cl}}_2\to {\mathrm{MgCl}}_2$

In the above chemical reaction, which atom is oxidized and which atom is reduced?