Question

Question 8

Look at the figures given below, which show three situations (a) burning candle (b) an extinguished candle (c) melting wax.
Which of these shows a reversible change and why?

Answer 1

The burning of candle produces carbon dioxide gas water vapour and soot, all of which go into the air and cannot be brought back to get the original candle. So, burning of a candle is an irreversible change. It's the same with the extinguished candle too. In the third situation i.e melting wax, the solid wax gets converted into liquid wax which on cooling gets converted back into the solid wax.