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Hydrogen

Short Answer Type

121. Write chemical reactions to show amphoteric nature of water.

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122.

Give two chemical reactions in which water acts as a reducing agent.

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123.

Give two points to distinguish between fresh tap water and distilled water.

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124.
Water has some air dissolved in it. What is its significance?

Air dissolved in water has the following advantages:
(i) Oxygen present in water is very useful for giving life to fish and other sea animals in the water.

(ii) Carbondioxide dissolved in water is very useful for carrying out photosynthesis in plants.

(iii) Carbon dioxide dissolved in water reacts with calcium carbonate present in marble rocks to produce calcium bicarbonate which is soluble.

Marine organisms fulfil their requirement of calcium carbonate from calcium bicarbonate.