Question

Which of the following can be categorised as both chemical and physical change?

• A. Formation of curd from milk.
• B. Melting of wax in a candle.
• C. Both melting of wax and formation of curd from milk.
• D. None of these

Answer 1

The correct option is D

None of these

Formation of curd from milk is an irreversible change, as milk cannot be obtained back from curd.
Melting of wax in a candle is a reversible change, as wax can be solidified and can be converted back to a candle.
But in general, there is no reaction which is both reversible as well as irreversible.