Question

How will you show that exhaled air has more carbon dioxide than inhaled air?

Answer 1

Carbon dioxide turns lime water milky. Based on this principle, experiment can be designed to show that exhaled air has more carbon dioxide than inhaled air.

• Take two test tubes half filled with lime water.
• With the help of glass tubes, clips and stoppers having two holes, set up an apparatus as shown below:

• The middle rubber tube is used to breath in and out through the mouth.
• Suck air through the rubber tube and open clip X and close clip Y. The inhaled air passes through the lime water present in test tube A. Now, exhale through the tube again and close clip X and open clip Y. The exhaled air passes through the lime water in test tube B.
• The lime water in test tube B turns milky. This shows that exhaled air has more carbon dioxide.