To identify which reaction is a decomposition reaction, let’s first understand what a decomposition reaction is. A decomposition reaction is a type of chemical reaction where one compound breaks down into two or more simpler substances.
Now, let's examine the given chemical reactions one by one:
A. [tex]\(2 KClO_3 \rightarrow 2 KCl + 3 O_2\)[/tex]
- Here, potassium chlorate ([tex]\(KClO_3\)[/tex]) is breaking down into potassium chloride ([tex]\(KCl\)[/tex]) and oxygen ([tex]\(O_2\)[/tex]).
- This indicates that one compound, [tex]\(2 KClO_3\)[/tex], is decomposing into multiple simpler substances, [tex]\(2 KCl\)[/tex] and [tex]\(3 O_2\)[/tex].
B. [tex]\(4 Na + O_2 \rightarrow 2 Na_2O\)[/tex]
- In this reaction, sodium ([tex]\(Na\)[/tex]) and oxygen ([tex]\(O_2\)[/tex]) are combining to form sodium oxide ([tex]\(Na_2O\)[/tex]).
- This is a combination (or synthesis) reaction, not a decomposition reaction.
C. [tex]\(ZnS + 3 O_2 \rightarrow 2 ZnO + 2 SO_2\)[/tex]
- Here, zinc sulfide ([tex]\(ZnS\)[/tex]) is reacting with oxygen ([tex]\(O_2\)[/tex]) to form zinc oxide ([tex]\(ZnO\)[/tex]) and sulfur dioxide ([tex]\(SO_2\)[/tex]).
- This is a combustion reaction, not a decomposition reaction.
D. [tex]\(2 NaBr + CaF_2 \rightarrow 2 NaF + CaBr_2\)[/tex]
- In this reaction, sodium bromide ([tex]\(NaBr\)[/tex]) reacts with calcium fluoride ([tex]\(CaF_2\)[/tex]) to form sodium fluoride ([tex]\(NaF\)[/tex]) and calcium bromide ([tex]\(CaBr_2\)[/tex]).
- This is a double displacement reaction, not a decomposition reaction.
Based on the definitions and the examination of each reaction, the correct decomposition reaction is:
A. [tex]\(2 KClO_3 \rightarrow 2 KCl + 3 O_2\)[/tex]
Therefore, the correct answer is A.
