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CBSE-IX-Science

12: 2-The Fundamental Unit of Life

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  • #9
    Carry out the following osmosis experiment:

    Take four peeled potato halves and scoops each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,
    (a) Keep cup A empty
    (b) Put one teaspoon sugar in cup B
    (c) Put one teaspoon salt in cup C
    (d) Put one teaspoon sugar in the boiled potato cup D.

    Keep these for two hours. Then observe the four potato cups and answer the following:
    (d) Explain why water gathers in the hollowed portion of B and C.
    (d) Why is potato A necessary for this experiment?
    (d) Explain why water does not gather in the hollowed out portions of A and D.
    (a) Keep cup A empty
    (b) Put one teaspoon sugar in cup B
    (c) Put one teaspoon salt in cup C
    (d) Put one teaspoon sugar in the boiled potato cup D.

    Keep these for two hours. Then observe the four potato cups and answer the following:
    (d) Explain why water gathers in the hollowed portion of B and C.
    (d) Why is potato A necessary for this experiment?
    (d) Explain why water does not gather in the hollowed out portions of A and D.
    Ans : i) When we put one teaspoon sugar in cup B and one teaspoon salt in cup C, the hypertonic solution is formed inside so through osmosis water from outside enters inside and collects in the hollowed portion of cups B & C.

    ii) Potato A is necessary to observe osmosis.

    iii) In hollowed out portion of A & D there is no solution (liquid medium) present therefore osmosis cannot take place and as a result water does not gather.
    (a) (b) (c) (d) (d) (d) (d) (a) (b) (c) (d) (d) (d) (d)
  • #9-a
    Keep cup A empty
  • #9-b
    Put one teaspoon sugar in cup B
  • #9-c
    Put one teaspoon salt in cup C
  • #9-d
    Put one teaspoon sugar in the boiled potato cup D.

    Keep these for two hours. Then observe the four potato cups and answer the following:
  • #9-d-i
    Explain why water gathers in the hollowed portion of B and C.
  • #9-d-ii
    Why is potato A necessary for this experiment?
  • #9-d-iii
    Explain why water does not gather in the hollowed out portions of A and D.