To determine which chemical equation represents a synthesis reaction, we first need to understand what a synthesis reaction is.
A synthesis reaction, or combination reaction, occurs when two or more reactants combine to form a single product. The general form of a synthesis reaction can be written as:
[tex]\[ A + B \rightarrow AB \][/tex]
Let's evaluate each option given in the question:
A. [tex]\[ H_2CO_3 \rightarrow H_2O + CO_2 \][/tex]
This represents a decomposition reaction, where a single compound breaks down into two or more simpler substances.
B. [tex]\[ 2 Na + MgCl_2 \rightarrow 2 NaCl + Mg \][/tex]
This equation represents a single displacement reaction, where one element replaces another in a compound.
C. [tex]\[ HCl + LiOH \rightarrow LiCl + H_2O \][/tex]
This is a double displacement reaction, which occurs when two compounds exchange ions or bonds to form different compounds.
D. [tex]\[ C + O_2 \rightarrow CO_2 \][/tex]
This equation fits the definition of a synthesis reaction because carbon (C) and oxygen (O_2) react to form a single product, carbon dioxide (CO_2).
From the analysis, it is clear that the equation [tex]\( C + O_2 \rightarrow CO_2 \)[/tex] (Option D) represents a synthesis reaction.
Therefore, the answer is:
D. [tex]\( C + O_2 \rightarrow CO_2 \)[/tex]
This conclusion aligns with the characteristics of synthesis reactions, where multiple reactants combine to form a single product.
