Petrochemistry is an example of

Step 1: Analyze the question The question asks which branch of chemistry petrochemistry belongs to.

Step 2: Explain the concept

• Pure chemistry studies chemical principles and theory for the sake of knowledge (e.g., atomic structure, bonding).
• Applied chemistry uses chemical principles to solve practical, industrial, or commercial problems (e.g., petrochemistry, pharmaceuticals, metallurgy, food technology).
• Biochemistry studies chemical processes in living organisms (e.g., enzymes, proteins, metabolism).
• Environmental chemistry studies chemical processes in the environment (e.g., pollution, water and soil chemistry).

Step 3: Apply to the question Petrochemistry deals with petroleum and natural gas and how they are processed into useful products such as petrol, plastics, fertilizers, synthetic fibres, detergents, and paints. This is a practical, industrial use of chemistry, not a study of theory alone. It is not about living organisms, and it is not mainly about studying the environment.

Step 4: Answer Petrochemistry is an example of applied chemistry, which is option A.

Tip: Ask yourself, "Is this chemistry being used to make or do something practical?" If yes, it is usually applied chemistry. Think of Nigeria's refineries and the Dangote petrochemical industry, which are real-life examples of applied chemistry.