Question

(a) What are the various ways in which a chemical equation can be made more informative? Give examples to illustrate your answer.
(b) Write balanced chemical equation from the following information:
An aqueous calcium hydroxide solution (lime water) reacts with carbon dioxide gas to produce a solid calcium carbonate precipitate and water.

Answer 1

(a) A chemical equation can be made more informative by:

• Indicating physical states of reactants and products.
• Indicating heat change in the reaction.
• Indicating the reaction condition.

Example:
2KClO₃ (s) + Heat $\stackrel{{\mathrm{MnO}}_2}{\to }$ 2KCl (s) + 3O₂ (g)

where,
(s) and (g) signifies solid and gaseous state of compounds, respectively.
Heat written on reactants' side signifies that the reaction consumes heat.
MnO₂ written above right-handed arrow signifies reaction takes place in the presence of MnO₂.

(b) The chemical equation for the given reaction reads as follows:
Ca(OH)₂ (aq) + CO₂ (g) $\to$ CaCO₃ (s) + H₂O (l)