Which of these require crystallization most?

Analyze the question: Crystallization is a separation and purification technique. A dissolved solid is made to form pure crystals by cooling or evaporating its solution. The question asks which industry depends on this process the most.

Explain the concept: Crystallization is used when a solid product must be highly pure and have a consistent form. Examples are:

• Sugar and salt refining
• Pharmaceutical production, where active drug ingredients are purified by crystallization (aspirin, paracetamol, and many antibiotics, for example)

Go through the options:

• A. Drug making: Drugs must be extremely pure. Crystallization is a key final step for purifying the active ingredient and controlling its crystal form, which affects how well it dissolves and works. This one fits best.
• B. Cement making: Cement is made by heating limestone and clay in a kiln, then grinding the product. This is thermal decomposition and milling, not crystallization.
• C. Paint making: Paint is made by mixing and dispersing pigments in a binder and solvent. It is a blending process, not crystallization.
• D. Perfume making: Perfume is made by extracting oils, then distilling, blending and dissolving them in alcohol. It relies on extraction and distillation, not crystallization.

Answer: Drug making needs crystallization most.

Exam tip: Link each separation method to its typical industry:

• Crystallization → purification of solids (drugs, sugar, salt)
• Distillation → perfumes, alcohol, petroleum
• Mixing and grinding → paint and cement