Which equation is a decomposition reaction?

A. [tex]Li_2CO_3 \rightarrow Li_2O + CO_2[/tex]

B. [tex]Zn + HCl \rightarrow ZnCl_2 + H_2[/tex]

C. [tex]Na_2O + CO_2 \rightarrow Na_2CO_3[/tex]

D. [tex]C_6H_{12}O_6 + O_2 \rightarrow CO_2 + H_2O[/tex]



Answer :

To identify which equation represents a decomposition reaction, let's first understand what a decomposition reaction entails. In a decomposition reaction, a single compound breaks down into two or more simpler substances.

Let's analyze each of the provided equations:

1. [tex]\( Li_2CO_3 \rightarrow Li_2O + CO_2 \)[/tex]:
- Here, Lithium carbonate ([tex]\(Li_2CO_3\)[/tex]) decomposes into Lithium oxide ([tex]\(Li_2O\)[/tex]) and Carbon dioxide ([tex]\(CO_2\)[/tex]). This fits the definition of a decomposition reaction.

2. [tex]\( Zn + HCl \rightarrow ZnCl_2 + H_2 \)[/tex]:
- In this reaction, Zinc ([tex]\(Zn\)[/tex]) reacts with Hydrochloric acid ([tex]\(HCl\)[/tex]) to form Zinc chloride ([tex]\(ZnCl_2\)[/tex]) and Hydrogen gas ([tex]\(H_2\)[/tex]). This is a single replacement reaction, not a decomposition reaction.

3. [tex]\( Na_2O + CO_2 \rightarrow Na_2CO_3 \)[/tex]:
- In this reaction, Sodium oxide ([tex]\(Na_2O\)[/tex]) reacts with Carbon dioxide ([tex]\(CO_2\)[/tex]) to form Sodium carbonate ([tex]\(Na_2CO_3\)[/tex]). This is a synthesis reaction, not a decomposition reaction.

4. [tex]\( C_6H_{12}O_6 + O_2 \rightarrow CO_2 + H_2O \)[/tex]:
- In this reaction, Glucose ([tex]\(C_6H_{12}O_6\)[/tex]) reacts with Oxygen ([tex]\(O_2\)[/tex]) to produce Carbon dioxide ([tex]\(CO_2\)[/tex]) and Water ([tex]\(H_2O\)[/tex]). This is a combustion reaction, not a decomposition reaction.

Based on the analysis, the first equation [tex]\( Li_2CO_3 \rightarrow Li_2O + CO_2 \)[/tex] clearly shows a single compound breaking down into two simpler substances. Thus, it is a decomposition reaction.

Therefore, the correct equation that represents a decomposition reaction is:

[tex]\[ Li_2CO_3 \rightarrow Li_2O + CO_2 \][/tex]