Which of the following reactions shows that the formation of [tex]$SO_2[tex]$[/tex] releases [tex]$[/tex]296.8 \, \text{kJ/mol}$[/tex]?

A. [tex]S(s) + O_2(g) \rightarrow SO_2(g) + 296.8 \, \text{kJ}[/tex]

B. [tex]S(s) + 2O(g) + 296.8 \, \text{kJ} \rightarrow SO_2(g)[/tex]

C. [tex]S(s) + O(g) \rightarrow SO_2(g) + 296.8 \, \text{kJ}[/tex]

D. [tex]S(s) + O_2(g) + 296.8 \, \text{kJ} \rightarrow SO_2(g)[/tex]



Answer :

To determine which reaction demonstrates that the formation of \(\text{SO}_2\) releases 296.8 kJ/mol, we need to understand what it means for a reaction to "release" energy. When a reaction releases energy, it is exothermic, meaning the energy (in the form of heat) is a product of the reaction.

Given this, let's analyze each option:

Option A: \( S \, (s) + O_2 \, (g) \rightarrow SO_2 \, (g) + 296.8 \, \text{kJ} \)

- In this reaction, \(\text{SO}_2\) is formed, and 296.8 kJ of energy is on the product side, indicating that this energy is released during the formation of \(\text{SO}_2\). This aligns with the concept of an exothermic reaction.

Option B: \( S \, (s) + 2 \, O \, (g) + 296.8 \, \text{kJ} \rightarrow SO_2 \, (g) \)

- Here, 296.8 kJ is on the reactant side, implying that energy is required (absorbed) for the reaction to occur. This describes an endothermic reaction, not an exothermic one.

Option C: \( S \, (s) + O \, (g) \rightarrow SO_2 \, (g) + 296.8 \, \text{kJ} \)

- Similar to Option A, this reaction shows 296.8 kJ as a product, indicating that this amount of energy is released during the reaction, hence exothermic.

Option D: \( S \, (s) + O_2 \, (g) + 296.8 \, \text{kJ} \rightarrow SO_2 \, (g) \)

- In this option, 296.8 kJ is again on the reactant side, indicating energy absorption, characteristic of an endothermic reaction.

Based on the analysis, the correct reaction that shows the formation of \(\text{SO}_2\) releases 296.8 kJ/mol is:

Option A: [tex]\( S \, (s) + O_2 \, (g) \rightarrow SO_2 \, (g) + 296.8 \, \text{kJ} \)[/tex]