Question

What can be concluded from the experiment shown below?

• A. Sunlight has no role in photosynthesis.
• B. Water is not required for photosynthesis to take place.
• C. Oxygen is evolved during photosynthesis
• D. Carbon dioxide is evolved during photosynthesis.

Answer 1

The correct option is C

Oxygen is evolved during photosynthesis

Air bubbles start moving from the cut end of the hydrilla twigs and get collected at the upper end of the test tube. After some time, we can see some gas getting collected at the top of the inverted test tube by downward displacement of water. To test the nature of the gas collected, the test tube can be removed quickly from the stem of the funnel and the mouth is to be closed with the thumb. Now, a glowing splinter or glowing incense stick can be introduced into the test tube by removing the thumb from the mouth of the test tube. The glowing splinter will immediately burst into a flame indicating that the gas collected in the test tube is oxygen.