Balance the following chemical equations:
(a) HNO3 + Ca(OH)2→ Ca(NO3)2 + H2O
(b) NaOH + H2SO4→ Na2SO4 + H2O
(c) NaCl + AgNO3→ AgCl + NaNO3
(d) BaCl2 + H2SO4→ BaSO4 + 2HCL
Step 1 - To balance chemical equations, first list the number of atoms of different type that are present in the chemical equation on both sides -
HNO3 + Ca(OH)2→ Ca(NO3)2 + H2O
| Element | No. of atoms in LHS | No. of atoms in RHS |
| N | 1 | 2 |
| Ca | 1 | 1 |
| H | 1+2 | 2 |
| O | 3+2 | 6+1 |
Step 2 - To start balancing, we find the compound that has the highest number of atoms. We can see that Ca(NO3)2 on the product side has the highest number of atoms. In this compound Oxygen has the highest number of atoms. Lets start with that.
| Atoms of O | In Reactant | In Product |
| Initial | 3 + 2 | 6 + 1 |
| Balanced | 2x3 + 2 | 6 + 2x1 |
This makes the partially balanced equation -
2HNO3 + Ca(OH)2→ Ca(NO3)2 + 2H2O
Step 3 - Now checking for all other elements we note that the number of atoms on both side are same. We can say that the equation is balanced.
Similarly we can balance the other equations and get the following results -
(a) 2HNO3 + Ca(OH)2→ Ca(NO3)2 + 2H2O
(b) 2NaOH + H2SO4→ Na2SO4 + 2H2O
(c) NaCl + AgNO3→ AgCl + NaNO3
(d) BaCl2 + H2SO4→ BaSO4 + 2HCL