Valid industrial applications of sulfuric acid

Steps:

• Evaluate use 1: Sulfuric acid does not act as a bleach; bleaching wood pulp uses chlorine compounds like hypochlorite.
• Evaluate use 2: Sulfuric acid is corrosive and unsafe for food; preservatives in tinned foods are benign agents like salt or benzoic acid.
• Evaluate use 3: Sulfuric acid serves as a sulfonating agent in detergent production, reacting with alkylbenzenes to form surfactants.
• Evaluate use 4: No valid use specified, but assuming common incorrect claim (e.g., direct fuel additive), it lacks industrial basis.

Why D is correct:

• Sulfuric acid (H₂SO₄) is a key reagent in sulfonation reactions for synthesizing detergent surfactants like sodium dodecyl sulfate.

Why the others are wrong:

• A includes 1 (incorrect bleaching) and 3 (correct but paired wrongly).
• B includes 2 (unsafe for food) and 4 (invalid use).
• C includes only 2 (not a food preservative).

Final answer: D