Let's analyze the given chemical reaction:
[tex]\[
2 \text{C}_8 \text{H}_{18} + 25 \text{O}_2 \longrightarrow 16 \text{CO}_2 + 18 \text{H}_2 \text{O}
\][/tex]
### Step-by-step breakdown:
1. Identify the type of reaction:
- The reaction given is a combustion reaction, as it involves a hydrocarbon (octane, \(\text{C}_8\text{H}_{18}\)) reacting with oxygen (\(\text{O}_2\)) to produce carbon dioxide (\(\text{CO}_2\)) and water (\(\text{H}_2\text{O}\)).
2. Check if it's a redox reaction:
- A redox (reduction-oxidation) reaction involves the transfer of electrons where the oxidation states of atoms change.
3. Determine the oxidation states of elements in the reactants and products:
- For \(\text{C}_8\text{H}_{18}\):
- Carbon in hydrocarbons generally has an oxidation state of \(-3\) because hydrogen is \(+1\).
- For \(\text{O}_2\):
- The oxidation state of the oxygen molecule (\(\text{O}_2\)) is \(0\) because it's in its elemental form.
- For \(\text{CO}_2\):
- Carbon in \(\text{CO}_2\) has an oxidation state of \(+4\) because oxygen is \(-2\).
- For \(\text{H}_2\text{O}\):
- Hydrogen is \(+1\) and oxygen is \(-2\).
4. Determine changes in oxidation states:
- Carbon in \(\text{C}_8\text{H}_{18}\) goes from \(-3\) (in \(\text{C}_8\text{H}_{18}\)) to \(+4\) (in \(\text{CO}_2\)). This is an increase in oxidation state, meaning carbon is being oxidized.
- Oxygen in \(\text{O}_2\) goes from \(0\) (in \(\text{O}_2\)) to \(-2\) (in \(\text{CO}_2\) and \(\text{H}_2\text{O}\)). This is a decrease in oxidation state, meaning oxygen is being reduced.
5. Identify the reducing and oxidizing agents:
- The substance that is oxidized (losing electrons) is the reducing agent.
- Here, the carbon in \(\text{C}_8\text{H}_{18}\) is oxidized, making \(\text{C}_8\text{H}_{18}\) the reducing agent.
### Conclusion:
The given reaction is indeed a redox reaction because there is a transfer of electrons as seen from the changes in oxidation states. The correct description of what is happening is:
[tex]\[
\text{This is a redox reaction in which octane (\(\text{C}_8\text{H}_{18}\)) is the reducing agent.}
\][/tex]
Thus, the best answer is:
[tex]\[
\text{This is a redox reaction in which octane (\(\text{C}_8\text{H}_{18}\)) is the reducing agent.}
\][/tex]
