Question

What was used to prove that source of oxygen evolved is water during photosynthesis

Answer 1

It was proved by the use of radioactive elements. For example, the water containing heavy oxygen (H2O18) was supplied to the leaves in place of natural oxygen, (H2O16).

On observation it was found that oxygen evolved in photosynthesis was heavy oxygen 1802 and not the natural oxygen.

Answer 2

Explanation:

Requirements: A large Beaker, SomeHydrillaPlant, One Funnel, One Testtube, water and a glowing splinter of wood.

Procedure: The Hydrilla plant should be kept in the beaker and coveredwith the funnel. Hydrilla plant be placed in such a way that its cutting ends remain towards the stem of the funnel. Water should be poured in the beaker in such a way that the stem of the funnel kept beneath the water level. A test tube completely filled with water should be inverted over the stem of the funnel. At this position the experimental set should be placed in Sunlight (or underelectric light in the laboratory).Water Observation: After sometimes it will be Bubble seen that bubbles are coming out from the Test-tube Hydrilla plant and are accumulating in the Beaker test tube. After accumulation of some gas Funel the test tube should be taken out carefully Hydrilla plant and a glowing splinter of wood be thrusted into the test tube, it will burst into flame.

Conclusion: As the gas helps theglowing splinter to flame so the gas is Oxygen, because Oxygen does not flame itself but helps other to flame.