To determine which equation shows an oxidation reaction, we need to understand what an oxidation reaction entails. Oxidation involves either the gain of oxygen or the loss of hydrogen. Let's analyze each of the given reactions to see if they meet these criteria:
Option A: [tex]\( C + O_2 \rightarrow CO_2 \)[/tex]
- In this reaction, Carbon (C) is combining with Oxygen (O[tex]\(_2\)[/tex]) to form Carbon Dioxide (CO[tex]\(_2\)[/tex]).
- Carbon is gaining oxygen to form CO[tex]\(_2\)[/tex], which fits the definition of an oxidation reaction.
- Therefore, this is an oxidation reaction.
Option B: [tex]\( CaCO_3 \rightarrow CaO + CO_2 \)[/tex]
- In this reaction, Calcium Carbonate ([tex]\(CaCO_3\)[/tex]) is decomposing into Calcium Oxide ([tex]\(CaO\)[/tex]) and Carbon Dioxide ([tex]\(CO_2\)[/tex]).
- This reaction is primarily a decomposition reaction, and it does not directly show the gain of oxygen or the loss of hydrogen for a single element.
- Hence, this is not an oxidation reaction.
Option C: [tex]\( CaO + 2 HCl \rightarrow CaCl_2 + H_2O \)[/tex]
- In this reaction, Calcium Oxide ([tex]\(CaO\)[/tex]) reacts with Hydrochloric Acid (HCl) to form Calcium Chloride ([tex]\(CaCl_2\)[/tex]) and Water ([tex]\(H_2O\)[/tex]).
- This is a neutralization reaction and does not involve a clear gain of oxygen or loss of hydrogen for any single element.
- Thus, this is not an oxidation reaction.
Option D: [tex]\( N_2O_4 \rightarrow 2 NO_2 \)[/tex]
- In this reaction, Dinitrogen Tetroxide ([tex]\(N_2O_4\)[/tex]) decomposes into Nitrogen Dioxide ([tex]\(NO_2\)[/tex]).
- Although the molecules are being rearranged, there is no single element undergoing a gain of oxygen or loss of hydrogen.
- Therefore, this is not an oxidation reaction.
From the detailed analysis, we conclude that Option A [tex]\( C + O_2 \rightarrow CO_2 \)[/tex] is the correct answer because Carbon gains oxygen to form Carbon Dioxide, which characterizes an oxidation reaction.
So, the equation that shows an oxidation reaction is:
(A) [tex]\( C + O_2 \rightarrow CO_2 \)[/tex].
