What is created when chlorine is added to water that is low in dissolved oxygen and has hydrogen sulfide?

When chlorine is added to water that contains hydrogen sulfide, an oxidation-reduction reaction occurs. Chlorine reacts with hydrogen sulfide (H₂S), which is a reduced form of sulfur, and through this reaction, elemental sulfur (S) can be formed. This is because chlorine acts as a strong oxidizing agent, capable of oxidizing hydrogen sulfide to form sulfur and other substances.

In situations where there is low dissolved oxygen in the water, the effectiveness of chlorine to oxidize contaminants like hydrogen sulfide becomes apparent. The addition of chlorine facilitates the conversion of the chemically reduced hydrogen sulfide to elemental sulfur, which may precipitate out of the solution.

The other choices involve different chemical processes or products that do not directly stem from the reaction of chlorine with hydrogen sulfide in low-oxygen conditions. Chloramines are formed when chlorine reacts with ammonia, chlorine gas is the form of chlorine that is added to the water but does not represent a product of that specific reaction, and sulfate particles result from the oxidation of hydrogen sulfide but are not the immediate product when chlorine reacts with it.