Question

A small quantity of curd is added to warm milk. The milk is stirred and is set aside for a few hours at a warm place. In a few hours, the milk changes into curd. How do you name this change and why?

• A. Curd cannot be converted back to milk.
• B. Curd can be converted back to milk.
• C. Sometimes curd can be reverted back to milk and sometimes not.
• D. No change is happening.

Answer 1

The correct option is D

No change is happening.

After curd is formed, it cannot be converted back to milk, so this change is an irreversible change. Irreversible changes are chemical changes where new products are formed which cannot be converted back to the original matter.