Question

How can you show that exhaled air contains carbon dioxide gas?

Answer 1

Breathing is the process in which we inhale oxygen and exhale carbon dioxide and this can be proved by the following experiments:

• Take 2 beakers and each filled with 5-10ml of lime water$\left(\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\right)$.
• Now in one beaker blow air from your mouth with the help of straw and in the second beaker blow a normal air.
• Now observe that a beaker that accepts the air from your moth turns milky quickly due to the high concentration of carbon dioxide in your exhaled air while the beaker that accepts the normal air takes a long time to turn milky because the concentration of carbon dioxide in the air is low.

This experiment shows that exhaled air contains a very high concentration of carbon dioxide.