Question

Which of the following are examples of chemical reactions?

i. Burning wood

ii. Cutting 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 wood - Chemical reaction ‐ the chemical composition of wood changes.

Cutting wood - Physical reaction - the chemical composition remains 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) due to the presence of moisture.

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