Question

Which of the given changes is a chemical change?

1. Dissolving sugar in water.
2. Burning of Magnesium ribbon.
3. Cutting of wood
4. Melting of ice

Answer 1

Correct Answer - Option 2 : Burning of Magnesium ribbon.

The correct answer is the Burning of Magnesium ribbon.

CONCEPT:

Chemical change	A change in which one or more new substance is formed is a chemical change. It is a permanent change
Physical change	Physical change: A change in which the physical properties of a substance undergoes change is called a physical change. It is a temporary change and no new substances are formed. It is generally reversible.

EXPLANATION:

• The burning of magnesium ribbon is a chemical change.
• Magnesium ribbon when introduced to a flame burns by forming a white powder of Magnesium oxide.
• 2Mg + O₂ → 2MgO
• This reaction produces intense heat and light.
• All the other given changes are physical changes because no new substance is formed; only a change of state takes place.