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

Answer 1

The correct option is D Melting of wax

$\bullet$ The change in which the composition of the original substance remains unchanged and no new substance is formed is called physical change.

$\bullet$ The changes that can be reversed or undone are called reversible changes.

$\bullet$ 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.

$\bullet$ While others fall under irreversible chemical change as new substances with different chemical properties are formed.