Which of the following reactions results in the oxidation of sulfur?

• A. S + O_2 ightarrow SO_2
• B. H_2S + Cl_2 ightarrow S + 2 HCl
• C. SO_2 + 2 H_2S ightarrow 3 S + 2 H_2O
• D. SO_2 + 2 H_2O ightarrow H_2SO_4 + 2 H_2

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the concept of oxidation in terms of oxidation states. Oxidation involves an increase in the oxidation state of an element during a chemical reaction.
2. Step 2: Assign oxidation numbers to sulfur in each reactant and product for all given reactions. For example, in elemental sulfur (S), the oxidation state is 0; in sulfur dioxide (SO_2), sulfur typically has an oxidation state of +4.
3. Step 3: Compare the oxidation states of sulfur on the reactant side and the product side for each reaction. Identify if the oxidation state of sulfur increases, which indicates oxidation.
4. Step 4: For the reaction \(S + O_2 \rightarrow SO_2\), sulfur goes from 0 to +4, showing an increase in oxidation state, meaning sulfur is oxidized.
5. Step 5: For the other reactions, check if sulfur's oxidation state decreases or remains the same, indicating reduction or no oxidation. The reaction where sulfur's oxidation state increases is the one that results in oxidation of sulfur.