Question

Which of the following changes is/are a chemical change?

• A. Formation of curd from milk
• B. Dissolution of sugar in water
• C. Shredding a sheet of paper into bits
• D. Cooking of food

Answer 1

Answer: (A), (D)

The correct options are
A Formation of curd from milk
D Cooking of food

The formation of curd from milk is a chemical change, as the enzymes secreted by the bacteria Lactobacillus converts milk into curd. Similarly, cooking is also a chemical change. The dissolution of sugar in water and shredding a piece of paper are examples of a physical change as no chemical reaction is involved in the processes.