Question

CASE STUDY 2 The Figure shown below represents an activity to prove the requirements for photosynthesis. During this activity, two healthy potted plants were kept in the dark for 72 hours. After 72 hours, KOH is kept in the watch glass in setup X and not in setup Y. Both these setups are air tight and have been kept in light for 6 hours. Then, lodine Test is performed with one leaf from each of the two plants X and Y. Bolt containing potassium hydroxide 53. This experimental set up is used to prove essentiality of which of the following requirements of photosynthesis? A. Chlorophyll B. Oxygen C. Carbon dioxide D. Sunlight 54. The function of KOH is to absorb A. Oxygen B. Carbon dioxide. C. Moisture. D. Sunlight 55. A. Blue - black colour would be obtained on the leaf of plant Xand no change in colour on leaf of plant Y. B. Blue - black colour would be obtained on the leaf of plant Y and no change in colour on leaf of plant X. C. Red colour would be obtained on the leaf of plant X and brown colour on the leaf of plant Y. D. Red colour would be obtained on the leaf of plant Y and brown colour on the leaf of plant X. 56. Which of the following steps can be followed for making the apparatus air tight? i. placing the plants on glass plate ii, using a suction pump. m. applying aseline to seal the bottom of jar. iv. creating vacuum Aiandi B. ii. and ili C. i. and in D. il. and iv​

Answer 1

Answer:

c is the answer

Explanation

carbon dioxide

Answer 2

53. - C - Carbon Dioxide

54. - B - Carbon Dioxide

55. - B - Blue-black colour would be obtained on the leaf of plant Y and no change in colour on the leaf of plant X.

56. - B - ii. and iii

Explanation:

• This experiment uses KOH to reduce Carbon Dioxide content to zero in a sealed jar so clearly, it is used to test the necessity of CO2
• KOH absorbs CO2 as  $KOH + CO_2 \to K_2CO_3 + H_2O$
• Blue-black colour would be obtained on the leaf of plant Y and no change in colour on the leaf of plant X as plant Y will still have starch content that will react with the IODINE solution but plant X will have no starch
• Both (ii) & (iii) are scientifically acceptable ways to ensure that the container remains airtight