Which of the following substances cannot be classified as a heavy chemical?

Analyze the question "Heavy chemicals" are industrial chemicals produced in very large quantities (thousands of tonnes) and used as raw materials for making many other products. Typical examples: sulphuric acid, sodium carbonate, sodium hydroxide, hydrochloric acid, nitric acid, ammonia, lime, bleaching powder, and fertilizers.

Explain the concept Heavy chemicals are:

• Made on a very large industrial scale
• Cheap and used in bulk
• Raw materials for many industries (soap, glass, paper, textiles, fertilizers, water treatment)

Fine or speciality chemicals, by contrast, are made in small quantities, are costly, and have specialized uses (e.g. in photography, pharmaceuticals, laboratory work).

Go through the options

• A. AgNO₃ (silver nitrate): Silver is a precious metal, so this compound is expensive and produced in small quantities. It is used in photography, laboratory analysis, and medicine. This is a fine chemical, not a heavy chemical.
• B. CaO (quicklime): Produced in huge quantities for cement, steel making, and agriculture. It is a heavy chemical.
• C. CaOCl₂ (bleaching powder): Made in bulk for bleaching and water treatment. It is a heavy chemical.
• D. H₂SO₄ (sulphuric acid): The classic heavy chemical, often called the "king of chemicals". It is a heavy chemical.

Answer: A. AgNO₃ is the substance that cannot be classified as a heavy chemical.

Exam tip: Think "bulk and cheap = heavy." If a compound contains a precious metal (silver, gold, platinum), it is almost certainly a fine chemical. Remember the common heavy chemicals: H₂SO₄, HNO₃, HCl, NaOH, Na₂CO₃, NH₃, CaO, bleaching powder.