Question

Give three points to prove curdling of milk to be a chemical change.

Answer 1

Answer:

Curd setting is a chemical change that occurs when a new substance (lactic acid) is formed. The resulting curd tastes different from the original substance. Furthermore, once the curd has formed, milk cannot be obtained from it. It is a permanent change.

Explanation:

When milk is curdled, the liquid form of milk becomes solid, resulting in the formation of curd. Because curdling milk produces curd with different chemical properties than milk, the process is classified as a chemical change. Milk contains casein protein, which interacts with lactic acid. Lactic acid dissolves milk's chemical structures/bonds and creates new ones, resulting in curd, a semi-solid form of milk. As a result, curdling milk is a chemical process.