Question

Select the incorrect statement with respect to the composition of clean air.

• A. Nitrogen makes 78% of the air
• B. Oxygen makes 21% of the air
• C. Carbon dioxide makes 1% of the air
• D. Argon makes 0.9% of the air

Answer 1

The correct option is C Carbon dioxide makes 1% of the air

The clean, dry air consists mainly of nitrogen at 78 per cent and oxygen at 21 per cent by volume. The remaining 1 per cent consists of a mixture of other gases, like argon at 0.9 per cent, along with traces of carbon dioxide, methane, hydrogen, helium, and water vapour.