When potassium chlorate is heated, potassium chloride and oxygen are formed. What type of chemical reaction is it?
a. Combination reaction
b. Displacement reaction
c. Decomposition reaction
d. Acid-base reaction
The Correct Answer and Explanation is:
The correct answer is c. Decomposition reaction.
Explanation:
A decomposition reaction is a type of chemical reaction where a single compound breaks down into two or more simpler substances, usually under the influence of heat, light, or electricity. The general form of a decomposition reaction is:
[
\text{AB} \rightarrow \text{A} + \text{B}
]
In the case of potassium chlorate (KClO₃), when it is heated, it breaks down into potassium chloride (KCl) and oxygen gas (O₂). The chemical equation for this reaction is:
[
2 \text{KClO₃} \xrightarrow{\text{heat}} 2 \text{KCl} + 3 \text{O₂}
]
This is a typical example of a decomposition reaction because potassium chlorate decomposes into two simpler products: potassium chloride and oxygen gas.
Why Other Options Are Incorrect:
- a. Combination reaction: In a combination reaction, two or more reactants combine to form a single product. For example, if hydrogen and oxygen combine to form water (H₂ + O₂ → H₂O), it is a combination reaction. This is not the case here, as potassium chlorate is breaking down into two substances, not combining.
- b. Displacement reaction: A displacement reaction occurs when one element displaces another in a compound. For example, in the reaction of zinc with hydrochloric acid (Zn + 2HCl → ZnCl₂ + H₂), zinc displaces hydrogen. In the potassium chlorate reaction, no element is displacing another; rather, potassium chlorate is breaking down.
- d. Acid-base reaction: An acid-base reaction typically involves the reaction of an acid and a base to form water and a salt. For example, hydrochloric acid reacting with sodium hydroxide (HCl + NaOH → NaCl + H₂O) is an acid-base reaction. Potassium chlorate breaking down does not involve an acid or a base, ruling this out.
Thus, the reaction involving the breakdown of potassium chlorate into potassium chloride and oxygen is a classic decomposition reaction.