Question

The major raw materials used in the manufacture of sulphuric acid by the contact process are:

• A. Sulphur, air and water
• B. Sulphur dioxide, nitric acid and water
• C. Pyrite, limestone and water
• D. Sulphuric acid and oleum

Hint:

Logic Tip: Look at the chemical formula of Sulfuric Acid: $H_2SO_4$. You need Sulphur (S), Oxygen (O from Air), and Hydrogen/Oxygen (H/O from Water). Option A provides exactly these basic building blocks.

Answer 1

The Correct Option is A

Concept:
The Contact Process is the modern industrial method for producing high-concentration sulfuric acid ($H_2SO_4$). Identifying the fundamental raw inputs requires tracing the chemical sequence back to its starting point.

Step 1:
The process begins by producing sulfur dioxide ($SO_2$). This is typically achieved by burning elemental Sulphur in the presence of Oxygen.

Step 2:
The Oxygen needed to burn the sulphur (and for later oxidation steps) is simply sourced from atmospheric Air.

Step 3:
The $SO_2$ is then catalytically oxidized by more Air over a Vanadium Pentoxide ($V_2O_5$) catalyst to form sulfur trioxide ($SO_3$).

Step 4:
The $SO_3$ is absorbed into existing sulfuric acid to form Oleum ($H_2S_2O_7$), which is then carefully diluted with Water to yield highly concentrated sulfuric acid.

Step 5:
Ignoring intermediate chemicals created inside the plant and catalysts that aren't consumed, the fundamental raw materials entering the factory gates are Sulphur, Air, and Water.