When water is added to calcium oxide, calcium hydroxide is formed and the container becomes hot. Which two types of reaction does this represent?
Answer and explanation
Correct answer: Combination and exothermic
The reaction is \(\mathrm{CaO + H_2O \rightarrow Ca(OH)_2}\). Two reactants combine to form a single product, calcium hydroxide, so it is a combination reaction. The container becoming hot indicates that heat is released; therefore, it is also exothermic. In contrast, a decomposition reaction involves one compound breaking down into two or more products.
Frequently asked questions
What is the correct answer to this question?
Combination and exothermic
Why is this the correct answer?
The reaction is \(\mathrm{CaO + H_2O \rightarrow Ca(OH)_2}\). Two reactants combine to form a single product, calcium hydroxide, so it is a combination reaction. The container becoming hot indicates that heat is released; therefore, it is also exothermic. In contrast, a decomposition reaction involves one compound breaking down into two or more products.
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.
