Question

Let 'X' be a type of change that falls under the category of both physical and reversible change. Which among the following processes could 'X' be?

• A. Rusting of iron
• B. Burning of wood
• C. Melting of wax
• D. Curdling of milk

Answer 1

The correct option is C Melting of wax

The change in which the composition of the original substance remains unchanged and no new substance is formed is called physical change.
The changes that can be reversed or undone are called reversible changes.
On heating, candle wax melts and forms liquid wax. Melting of wax is a physical reversible change as no new products are formed and on cooling it turns into solid wax. While others fall under irreversible chemical change as new substances with different chemical properties are formed.