Question

Write the chemical formulae and hence balance the following word equation

Ammonium chloride+calcium hydroxide$\to$calcium chloride+ammonia+water

Answer 1

Balanced chemical equation: A balanced chemical equation represents an equation in which the number of atoms of each element is equal on both the reactant and product sides.

Balancing of given reaction:

Step 1: Calculating the number of atoms on both sides of the reaction

Ammonium chloride reacts with calcium hydroxide to form Calcium chloride, ammonia, and water.

$\underset{\mathrm{Calcium}\mathrm{hydroxide}}{\mathrm{Ca}{\left(\mathrm{OH}\right)}_2}+\underset{\mathrm{Ammonium}\mathrm{chloride}}{{\mathrm{NH}}_4\mathrm{Cl}}\to \underset{\mathrm{Calcium}\mathrm{chloride}}{{\mathrm{CaCl}}_2}+\underset{\mathrm{Ammonia}}{{\mathrm{NH}}_3}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}}$

Elements	Number of atoms on the reactant side	Number of atoms on the product side
$\mathrm{Ca}$	1	1
$\mathrm{O}$	2	1
$\mathrm{H}$	6	5
$\mathrm{N}$	1	1
$\mathrm{Cl}$	1	2

Step 2: Balancing the uneven number of atoms on the reactants and product side

• As the atoms of each element are not equal on both sides of the reaction we need to add stoichiometric coefficients to balance each element
• To balance the chlorine we multiply the reactant side with ‘2’
• To balance the nitrogen we multiply the product side with ‘2’
• To balance the hydrogen we multiply the product side with ‘2’

The equation becomes: $\underset{\mathrm{Calcium}\mathrm{hydroxide}}{\mathrm{Ca}{\left(\mathrm{OH}\right)}_2}+\underset{\mathrm{Ammonium}\mathrm{chloride}}{2{\mathrm{NH}}_4\mathrm{Cl}}\to \underset{\mathrm{Calcium}\mathrm{chloride}}{{\mathrm{CaCl}}_2}+\underset{\mathrm{Ammonia}}{2{\mathrm{NH}}_3}+\underset{\mathrm{Water}}{2{\mathrm{H}}_2\mathrm{O}}$

Elements	Number of atoms on the reactant side	Number of atoms on the product side
$\mathrm{Ca}$	1	1
$\mathrm{O}$	2	2
$\mathrm{H}$	10	10
$\mathrm{N}$	2	2
$\mathrm{Cl}$	2	2

The final balanced reaction is : $\underset{\mathrm{Calcium}\mathrm{hydroxide}}{\mathrm{Ca}{\left(\mathrm{OH}\right)}_2}+\underset{\mathrm{Ammonium}\mathrm{chloride}}{2{\mathrm{NH}}_4\mathrm{Cl}}\to \underset{\mathrm{Calcium}\mathrm{chloride}}{{\mathrm{CaCl}}_2}+\underset{\mathrm{Ammonia}}{2{\mathrm{NH}}_3}+\underset{\mathrm{Water}}{2{\mathrm{H}}_2\mathrm{O}}$