Question

Which one of the following processes involve chemical reactions?

• A. Storing of oxygen gas under pressure in a gas cylinder
• B. Liquefaction of air
• C. Keeping petrol in a china dish openly
• D. Heating copper wire in presence of air at high temperature

Answer 1

The correct option is D Heating copper wire in presence of air at high temperature

Heating copper wire in presence of air is a chemical reaction, as copper reacts with oxygen ($O_2$) to form a new product as cupric oxide ($CuO$).

$2Cu\left(s\right)+O_2\left(g\right)\to 2CuO\left(s\right)$