Q22 of 33 Page 1

What do you observe when you drop a few drops of acetic acid to a test tube containing:

a) Phenolphthalein


b) Universal indicator


c) distilled water


d) sodium hydrogen carbonate.

a) It will remain colourless


b) It will dissolve in distilled water forming a clear solution.


c) The solution will turn orange.


d) Brisk effervescence will be formed with evolution of carbon dioxide.


NaHCO3 + CH3COOH → CH3COONa +H2O + CO2


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21

(a) “Improvements in our lifestyle have resulted in greater amounts of waste generation.” Give two examples to support the given statement. Suggest one change that we can incorporate in our lifestyle in order to reduce nonbiodegradable waste.

(b) The following organisms form a food chain. Insect, Hawk, Grass, Snake, Frog Which of these will have highest concentration of non-biodegradable chemicals? Name the phenomenon.

 21

(a) What do you understand by “Watershed Management”? List any two advantages of watershed management.

(b) “Human beings occupy the top level in any food chain.” What are the consequences of this on our body?

 23

Riya performs two set of experiments to study the length of the foam formed which are as follows:

Set I: she takes 10 ml of distilled water in a test tube “A” and adds 5-6 drops of liquid soap in it and shakes the test tube vigorously.


Set II: she takes 10 ml of distilled water in a test tube “A” and adds 5-6 drops of liquid soap with half spoonful of CaSO4 in it and shakes the test tube. Write your observation and reason.

 24

A student observed a permanent slide showing asexual reproduction in yeast. Draw diagrams of the observations he must have made from the slide. Name the process also.