NH4Cl+Ca(OH)2⟶CaCl2+NH3+H2O(i) First calculate number of atoms of each element on reactant side and product side apart from H and O.
As we can see,
Number of Nitrogen= 1 on both side
Number of Ca=1 on both side
Number of Cl=2 on product side and 1 on reactant side
Thus we multiply reactant side Cl containing species by 2.
2NH4Cl+Ca(OH)2⟶CaCl2+NH3+H2O
(ii) Now, number of N=2 on reactant side and 1 on product side. Now, multiply N containing species by 2 on product side. We get,
2NH4Cl+Ca(OH)2⟶CaCl2+2NH3+H2O
(iii) Now, all the other elements except H & O has been balanced.
Calculate number of H & O on both side and multiply the required number with H2O to balance.
Number of H=10 on reactant side and 8 on product side.
Number of O=2 on reactant side and 1 on product side.
Thus, 2H and 1O is required for balance.
Then multiply H2O by 2, we get the balanced equation,
2NH4Cl+Ca(OH)3⟶CaCl2+2NH3+2H2O