Which energy change occurs when calcium oxide reacts with water to form calcium hydroxide?
Answer and explanation
Correct answer: Heat is released
The reaction is represented as CaO + H₂O → Ca(OH)₂ + heat. Formation of calcium hydroxide from quicklime and water releases considerable heat, so it is an exothermic reaction and option A is correct. Option B describes an endothermic change, while the reaction does not primarily produce light or electrical energy as stated in options C and D.
Frequently asked questions
What is the correct answer to this question?
Heat is released
Why is this the correct answer?
The reaction is represented as CaO + H₂O → Ca(OH)₂ + heat. Formation of calcium hydroxide from quicklime and water releases considerable heat, so it is an exothermic reaction and option A is correct. Option B describes an endothermic change, while the reaction does not primarily produce light or electrical energy as stated in options C and D.
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.
