Which one of the following is not a chemical change?
Ripening of fruits
Curdling of milk
Freezing of water
Digestion of food
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC NDA-1 – 2016
A) Ripening of fruits: Involves complex chemical reactions that change color, sweetness, texture, and aroma (e.g., conversion of starch to sugars, breakdown of pigments). This is a chemical change.
B) Curdling of milk: Usually caused by the action of acids or enzymes on milk proteins (casein), causing them to coagulate and separate from the liquid whey. This is a chemical change.
C) Freezing of water: Water changes from liquid state to solid state (ice). The chemical composition remains H₂O. This is a change of state, which is a physical change.
D) Digestion of food: Involves the breakdown of complex food molecules (carbohydrates, proteins, fats) into simpler molecules by enzymes. These are chemical reactions. This is a chemical change.
Therefore, freezing of water is not a chemical change; it is a physical change.