Question

Which of the following is both a reversible and an irreversible change?

• A. Formation of curd from milk.
• B. Rusting of iron
• C. There is no such case possible in general.
• D. Both rusting of iron and formation of curd from milk.

Answer 1

The correct option is C

There is no such case possible in general.

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 converted back to a candle.
But in general, there is no reaction which is both reversible as well as irreversible.