Which product is formed when water is added to calcium oxide?
Answer and explanation
Correct answer: Calcium hydroxide
Calcium oxide, \(\mathrm{CaO}\) (quicklime), reacts with water to form calcium hydroxide, \(\mathrm{Ca(OH)_2}\) (slaked lime):
\[\mathrm{CaO + H_2O \rightarrow Ca(OH)_2}\]
This is an exothermic reaction. Calcium carbonate requires \(\mathrm{CO_2}\) for its formation, so it is not produced by adding water alone.
Frequently asked questions
What is the correct answer to this question?
Calcium hydroxide
Why is this the correct answer?
Calcium oxide, \(\mathrm{CaO}\) (quicklime), reacts with water to form calcium hydroxide, \(\mathrm{Ca(OH)_2}\) (slaked lime):
\[\mathrm{CaO + H_2O \rightarrow Ca(OH)_2}\]
This is an exothermic reaction. Calcium carbonate requires \(\mathrm{CO_2}\) for its formation, so it is not produced by adding water alone.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
