Viraf J Dalal Chemistry Class 8 Icse Solutions Apr 2026

Maya smiled. She wrote confidently: Combination reaction. Iron + Oxygen → Iron(III) oxide. The increase in mass is due to the added oxygen from the air.

Maya groaned. “That’s cheating, Mom.” viraf j dalal chemistry class 8 icse solutions

Her father, a civil engineer, was busy with site plans. Her mother suggested, “Why not check the solution book?” Maya smiled

Suddenly, the concept clicked. She opened the solution book again — not to copy, but to her own answers to 10 practice questions. Each time, the solutions explained the reason , not just the final line. The increase in mass is due to the added oxygen from the air

Instead of just copying the answer, she read the carefully: Solution hint: In rusting, iron (Fe) from the nail combines with oxygen (O₂) from the air and water vapor to form hydrated iron(III) oxide (Fe₂O₃·xH₂O). The rust includes the original iron plus the added oxygen. Therefore, the total mass of the rusted nail is greater than the original nail. Then, Viraf J. Dalal’s book had a "Try This" box: Perform an activity – weigh a clean iron nail, leave it in moist cotton for 3 days, weigh again.

The topic? Physical and Chemical Changes — specifically, why a rusted nail weighed more than a new one. Her textbook said: “Rusting is oxidation. Iron combines with oxygen to form iron oxide.” But in her head, that made no sense. If something rusts and flakes away, shouldn’t it weigh less ?

Maya didn’t have 3 days, but she had a lightbulb moment: The rust isn’t just “damage.” It’s a new substance that captured invisible oxygen from the air.