To tackle this intriguing chemistry question, let’s break down the clues provided about the elements and compounds involved. We need to identify the elements A, B, C, and D based on their properties and reactions.
Identifying the Elements and Compounds
Starting with element A, which is described as a yellow solid in its standard state, we can deduce that it is likely sulfur (S). Sulfur is known for its yellow appearance and solid state at room temperature.
Next, we look at the volatile hydride B, which is a foul-smelling gas used in qualitative analysis. The hydride of sulfur is hydrogen sulfide (H₂S), which fits the description perfectly. Hydrogen sulfide is notorious for its rotten egg smell and is indeed used in qualitative analysis to detect metal ions.
Moving on to oxide C, which is formed when B reacts with oxygen. When hydrogen sulfide (H₂S) is burned in the presence of oxygen, it produces sulfur dioxide (SO₂). This gas is colorless and has a pungent smell, matching the description of oxide C.
Finally, we need to identify oxide D, which is formed when C is oxidized in the presence of a heterogeneous catalyst. Sulfur dioxide (SO₂) can be further oxidized to sulfur trioxide (SO₃) under certain conditions, particularly in the presence of a catalyst like vanadium pentoxide (V₂O₅). Thus, D is sulfur trioxide (SO₃).
Summary of Identifications
- A: Sulfur (S)
- B: Hydrogen sulfide (H₂S)
- C: Sulfur dioxide (SO₂)
- D: Sulfur trioxide (SO₃)
Chemical Reactions Involved
Now, let’s write the chemical equations for the reactions mentioned. First, we have the reaction of sulfur dioxide (C) with acidified potassium permanganate (KMnO₄). This reaction is a redox reaction where sulfur dioxide is oxidized to sulfuric acid (H₂SO₄), and the purple color of KMnO₄ is decolorized as it is reduced to manganese(II) ions (Mn²⁺).
Reaction with Acidified KMnO₄
The balanced equation for this reaction is:
5 SO₂ + 2 KMnO₄ + 6 H₂SO₄ → 5 H₂SO₄ + 2 MnSO₄ + K₂SO₄ + 3 H₂O
In this reaction, sulfur dioxide is oxidized to sulfuric acid, and the permanganate ion is reduced, resulting in the decolorization of the solution.
Conversion of C to D
Next, we consider the conversion of sulfur dioxide (C) to sulfur trioxide (D) in the presence of a catalyst. This reaction is part of the Contact Process used in the industrial production of sulfuric acid:
2 SO₂ + O₂ ⇌ 2 SO₃
This reaction is exothermic and typically occurs at elevated temperatures (around 450°C) and pressures, with vanadium pentoxide as the catalyst.
Final Thoughts
In summary, we identified the elements and compounds as follows: A is sulfur, B is hydrogen sulfide, C is sulfur dioxide, and D is sulfur trioxide. The reactions involving these compounds illustrate important concepts in redox chemistry and industrial processes. Understanding these relationships not only helps in qualitative analysis but also in practical applications like the production of sulfuric acid.
