Question

Balance the following unbalanced equations:

${\mathrm{CaCO}}_3+{\mathrm{H}}_3{\mathrm{PO}}_4\to {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

Answer 1

Steps involved in balancing a chemical reaction:

Step 1: Write the unbalanced equation.

${\mathrm{CaCO}}_3+{\mathrm{H}}_3{\mathrm{PO}}_4\to {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

Step 2: Write down the number of atoms of each elements present on both reactant as well as product side.

Element Reactant side Product side

$\mathrm{Ca}$ $1$ $3$

$\mathrm{C}$ $1$ $1$

$\mathrm{O}$ $7$ $11$

$\mathrm{H}$ $3$ $2$

$\mathrm{P}$ $1$ $2$

Step 3: Add coefficients to balance the number of atoms on both the sides

Firstly balance $\mathrm{Ca}$ at reactant side by adding $3$ before ${\mathrm{CaCO}}_3$.

$3{\mathrm{CaCO}}_3+{\mathrm{H}}_3{\mathrm{PO}}_4\to {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

Secondly balance $\mathrm{C}$ at product side by adding $3$ before ${\mathrm{CO}}_2$.

$3{\mathrm{CaCO}}_3+{\mathrm{H}}_3{\mathrm{PO}}_4\to {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2+{\mathrm{H}}_2\mathrm{O}+3{\mathrm{CO}}_2$

Thirdly balance $\mathrm{P}$ at reactant side by adding $2$ before ${\mathrm{H}}_3{\mathrm{PO}}_4$.

$3{\mathrm{CaCO}}_3+2{\mathrm{H}}_3{\mathrm{PO}}_4\to {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2+{\mathrm{H}}_2\mathrm{O}+3{\mathrm{CO}}_2$

Fourthly balance $\mathrm{H}$ at product side by adding $3$ before ${\mathrm{H}}_2\mathrm{O}$.

$3{\mathrm{CaCO}}_3+2{\mathrm{H}}_3{\mathrm{PO}}_4\to {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2+3{\mathrm{H}}_2\mathrm{O}+3{\mathrm{CO}}_2$

The balanced equation is:

$3{\mathrm{CaCO}}_3\left(\mathrm{s}\right)+2{\mathrm{H}}_3{\mathrm{PO}}_4\left(\mathrm{aq}\right)\to {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2\left(\mathrm{aq}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+3{\mathrm{CO}}_2\left(\mathrm{g}\right)$

Calcium carbonate Hydrogen phosphate Calcium phosphate Water Carbon di oxide