Answer: Option (C) is the correct answer.
Explanation:
When two different compounds combine to result in the formation of a new compound then this type of reaction is known as synthesis reaction.
On the other hand, when a compound decomposes to result in the formation of different compounds then it is known as decomposition reaction.
Therefore, the chemical equation for the given reaction is as follows.
[tex]MgCO_{3} + HNO_{3} \rightarrow MgNO_{3} + H_{2}CO_{3}[/tex]
[tex]H_{2}CO_{3} \rightarrow H_{2}O + CO_{2}[/tex]
Thus, we can see that carbonic acid dissociates to give water and carbon dioxide. Both water and carbon dioxide are compound.
Hence, we can conclude that it is a decomposition reaction; carbonic acid breaks down into two simpler compounds.
