What is the name of the acid formed when H_2S gas is dissolved in water?

• A. Hydrogen sulfide acid
• B. Hydrosulfuric acid
• C. Sulfuric acid
• D. Sulfurous acid

Answer: (B)

Verified step by step guidance

1. Recognize that when a gas dissolves in water and forms an acid, the acid is typically named based on the anion formed by the gas after it ionizes in water.
2. Identify the gas given: H_2S, which is hydrogen sulfide. When dissolved in water, it ionizes to form H^+ ions and HS^- or S^{2-} ions.
3. Recall the naming convention for binary acids (acids composed of hydrogen and one other nonmetal element): the prefix 'hydro-' is used, followed by the root of the nonmetal element, and ending with the suffix '-ic acid'.
4. Apply this rule to H_2S: the nonmetal is sulfur, so the acid formed is named 'hydrosulfuric acid'.
5. Understand that sulfuric acid (H_2SO_4) and sulfurous acid (H_2SO_3) are oxyacids of sulfur, which are different from the binary acid formed by dissolving H_2S gas in water.