Question

Which of the following are examples of chemical reactions?

i. Burning of wood

ii. Cutting of wood

iii. Conversion of steam to water

iv. Rusting of almirah

v. Dissolving common salt in water

• A. i, iv
• B. i, iii, v
• C. ii, iv, v
• D. v, ii, iii

Answer 1

The correct option is A

i, iv

Burning of wood - Chemical reaction ‐ the chemical composition of wood changes.

Cutting of wood - Physical reaction - the chemical composition remains the same, only the size of the wood changes.

Conversion of steam to water- Physical reaction - no change in chemical nature of the substance.

Rusting of almirah- Chemical reaction ‐ Iron present in almirah forms Iron oxide (new compound) dthe ue to presence of moisture.

Dissolving common salt in water‐ Physical Reaction ‐ no new compound is formed, the dissolved salt can be separated by evaporation.