Q.11:- Which of the following are chemical changes?
(a) Growth of a plant
(b) Rusting of iron
(c) Mixing of iron filings and sand
(d) Cooking of food
(e) Digestion of food
(f) Freezing of water
(g) Burning of a candle

Answer:-

(a) Growth of a plant, (b) rusting of iron, (d) cooking of food, (e) digestion of food and (g) burning of a candle, are chemical changes.