Advertisements
Advertisements
प्रश्न
How would you demonstrate that green plants release oxygen when exposed to light?
Advertisements
उत्तर
- Place some water plants (Elodea or Hydrilla) in a beaker containing pond water and cover them by a short-stemmed funnel.
- Invert a test tube full of water over the stem of the funnel. (Ensure that the level of water in the beaker is above the level of the stem of the inverted funnel.)
- Place the apparatus in the sun for a few hours (in Fig). Bubbles of the gas will collect in the test tube.
- Test the gas in the test tube. A glowing splinter bursts into flame, which shows the presence of oxygen.
APPEARS IN
संबंधित प्रश्न
A healthy oat seeding in a pot is transferred from light to any airy but completely dark room. How would it differ from its original condition in appearance after about a week? Explain the difference.
The diagram alongside refers to an experiment in which the apparatus was set up with the light source 10 cm away from the plant. After 15 minutes the number of bubbles evolved per minute from the cut stem was recorded. The light source was moved to 20 cm away from the plant, left for 15 minutes and the number of bubbles evolved per minute was again recorded. The experiment was repeated with the light source at distances of 40, 60, 80 and 100 cm away from the plant. Plot a graph for the results obtained and answer the following questions.
(i) From the graph it seems likely that the rate of bubbling per minute at 50 cm would have been
(a) 2.0 (b) 2.5 (c) 3.0 (d) 3.5
(ii) The gas produced by the plant during the experiment was
(a) air (b) oxygen (c) carbon dioxide (d) nitrogen (e) hydrogen
(iii) The gas collected comes due to the breakdown of
(a) glucose (b) starch (c) water (d) air (e) ATP
(iv) If ice cubes were added to the water, the rate of bubble formation would
(a) Stay the same.
(b) Increase because more water is added.
(c) Decrease because the temperature drops.
(d) Decrease because water freezes.
(e) Cannot tell from the information given.
(v) If some sodium bicarbonate is added to the water the rate of bubble formation
(a) Increases because more respiration occurs.
(b) Increases because more photosynthesis occurs.
(c) Increases because the gas becomes less soluble.
(d) Decreases because carbon dioxide acts as a limiting factor.
(e) Decreases because respiration decreases.
Given alongside is the diagram of an experimental set-up:
What alteration (s) will you make in it for obtaining expected result?
The diagram below shows two test-tubes A and B. Test-tube A contains a green water plant. Test-tube B contains both a green water plant and a snail. Both test-tubes are kept in sunlight. Answer the questions that follow:
(a) Name the physiological process that releases the bubbles of oxygen.
(b) Explain the physiological process as mentioned above in (a).
(c) What is the purpose of keeping a snail in test-tube B?
(d) Why does test-tube B have more bubbles of oxygen?
(e) Give an example of a water plant that can be used in the above experiment.
(f) Write the overall chemical equation for the above process.
Give technical term:
Name only one plant, you are familiar with which has no chlorophyll.
Choose the Correct Answer:
The main difference between chlorophyll ‘a’ and ‘b’ is:
Given below is the figure of an experimental set-up, showing a physiological act of the plants. Study and answer the following questions:
- What is the objective of this experiment?
- Name and define the process shown here.
- Why do we destarch the leaves before performing the experiment?
- How do we destarch the leaves?
- What will be the observation when we pour iodine solution over the bleached experimental leaf?
- Write a well-balanced equation for the above process.
Given below is the diagram of an experimental set-up (final stage). Study the same and answer the following questions:
- What is the main aim of the experiment?
- Oxygen gas shown in the experiment is released from which of the raw materials?
- How would you confirm the presence of oxygen gas?
- Name the chemical substance which can be added in water to enhance the process/rate of release of oxygen gas.
- Draw a neat and labelled diagram of the same experiment for its initial stage.
