Question

Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water

The balanced chemical equation for the following word equation is:

• A. ${\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to {\text{CaCO}}_3\text{(aq)}+{\text{H}}_2\text{O}\text{(l)}$
• B. ${\text{Ca(OH)}}_2\text{(aq)}+2{\text{CO}}_2\text{(g)}\to 2{\text{CaCO}}_3\text{(aq)}+{\text{H}}_2\text{O(l)}$
• C. $2{\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to 2{\text{CaCO}}_3\text{(aq)}+2{\text{H}}_2\text{O(l)}$
• D. $2{\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to {\text{CaCO}}_3\text{(aq)}+2{\text{H}}_2\text{O(l)}$

Answer 1

The correct option is A ${\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to {\text{CaCO}}_3\text{(aq)}+{\text{H}}_2\text{O}\text{(l)}$

The chemical equation for the given word equation is:

${\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to {\text{CaCO}}_3\text{(aq)}+{\text{H}}_2\text{O}\text{(aq)}$

On counting the number of atoms on both sides, we have:

- The number of calcium atom present on reactant and product side is 1.
- The number of oxygen atoms present on reactant and product side is 4.
- The number of hydrogen atoms present on reactant and product side is 2.
- The number of carbon atoms present on reactant and product side is 1.
Hence, the equation is already balanced.