Chemistry · Electronic concepts of oxidation and reduction, redox reactions, oxidation number, rules for assigning oxidation number and balancing of redox reactions

When the gases; sulphur dioxide and hydrogen sulphide mix in the presence of wat

When the gases; sulphur dioxide and hydrogen sulphide mix in the presence of water, the reaction \( S O_{2}+2 H_{2} S \rightarrow \) \( 2 H_{2} O+3 S \) occurs Here hydrogen sulphide is acting as:

  • A. an oxidizing agent
  • B. a reducing agent
  • C. a dehydrating agent
  • D. a catalyst

Step-by-step solution

In the reaction SO2 + 2H2S → 2H2O + 3S, the oxidation state of sulfur in SO2 is +4 and in H2S is -2. In the product (S), the oxidation state is 0. Thus, sulfur in SO2 is reduced (from +4 to 0), making SO2 the oxidizing agent. Sulfur in H2S is oxidized (from -2 to 0), making H2S the reducing agent. Hence, hydrogen sulphide acts as a reducing agent.
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