To determine which formula represents the burning of sulfur to produce sulfur dioxide (SO₂), we must analyze each given chemical equation. The goal is to find the equation that results directly in the production of sulfur dioxide (SO₂) from sulfur and oxygen.
Let's go through each option:
1. Option A:
[tex]\[ 2 H_2S (s) + 3 O_2 (g) \longrightarrow 2 H_2O (l) + 2 SO_2 (g) \][/tex]
This equation represents the combustion of hydrogen sulfide (H₂S) with oxygen to produce water (H₂O) and sulfur dioxide (SO₂). Although SO₂ is produced, the reactant involving sulfur is hydrogen sulfide, not elemental sulfur. Therefore, this equation does not directly represent the burning of sulfur to produce sulfur dioxide.
2. Option B:
[tex]\[ 4 FeS_2 + 11 O_2 \longrightarrow 2 Fe_2O_3 + 8 SO_2 \][/tex]
This equation represents the reaction of iron pyrite (FeS₂) with oxygen (O₂) to produce iron(III) oxide (Fe₂O₃) and sulfur dioxide (SO₂). Here, sulfur from FeS₂ reacts with oxygen to produce SO₂. Even though FeS₂ contains sulfur, this reaction quite closely represents the production of sulfur dioxide through the involvement of sulfur-containing compounds reacting with oxygen.
3. Option C:
[tex]\[ 2 SO_2(g) + O_2(g) \xrightarrow{V_2O_5} 2 SO_3(g) \][/tex]
This equation shows the oxidation of sulfur dioxide (SO₂) to sulfur trioxide (SO₃) using a vanadium (V) oxide catalyst. This reaction starts with sulfur dioxide rather than elemental sulfur, and the product is sulfur trioxide, not sulfur dioxide. Therefore, this equation does not represent the direct production of SO₂ from the burning of sulfur.
After reviewing the options, the equation that best represents the burning of sulfur to produce sulfur dioxide is:
[tex]\[ 4 FeS_2 + 11 O_2 \longrightarrow 2 Fe_2O_3 + 8 SO_2 \][/tex]
Thus, the correct answer is:
[tex]\[ \boxed{2} \][/tex]
