Calcium oxide reacts with water to form only calcium hydroxide, and the container becomes hot. Which conclusion is most complete?
Answer and explanation
Correct answer: It is both a combination and an exothermic reaction
The reaction is \(\mathrm{CaO + H_2O \rightarrow Ca(OH)_2}\). Since two reactants combine to form one product, it is a combination reaction. The container becoming hot shows that heat is released, so the reaction is also exothermic. In a decomposition reaction, one compound breaks into simpler substances, which does not occur here.
Frequently asked questions
What is the correct answer to this question?
It is both a combination and an exothermic reaction
Why is this the correct answer?
The reaction is \(\mathrm{CaO + H_2O \rightarrow Ca(OH)_2}\). Since two reactants combine to form one product, it is a combination reaction. The container becoming hot shows that heat is released, so the reaction is also exothermic. In a decomposition reaction, one compound breaks into simpler substances, which does not occur here.
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.
