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प्रश्न
What are stalgmites and stalactites? How are they formed?
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उत्तर
In some limestone caves, conical pillar-like objects hang from the roof and some rise from the floor. These are formed by water containing dissolved calcium hydrogen carbonate continuously dropping from the cracks in the rocks. Release of pressure results in the conversion of some hydrogen carbonate to calcium carbonate.
Ca(HCO3)2 → CaCO3 + CO2 + H2O
This calcium carbonate little by little and slowly deposit on both roof and floor of the cave.
The conical pillar which grows downwards from the roof is called stalactite and the one which grows upward from the floor of the cave is called stalagmite.
These meet after a time. In a year, some grow less than even a centimetre, but some may be as tall as 100 cm.
CaCO3 + CO2 + H2O → Ca(HCO3)2
MgCO3 + CO2 + H2O → Mg(HCO3)2
If the water flows over beds of gypsum (CaSO4.2H2O), a little bit of gypsum gets dissolved in water and makes it hard.
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संबंधित प्रश्न
Match the statements in column A with that in column B.
| Column A | Column B |
| (a) deliquescent substance | (1) sodium bicarbonate |
| (b) hygroscopic substance | (2) magnesium chloride |
| (c) efflorestance substance | (3) conc. sulphuric acid |
| (d) substance causing temporary hardness | (4) washing soda |
Describe the water-cycle in nature.
Answer the following question:
What is the chemical composition of water ? Give its molecular formula.
Why is water considered a compound?
Name the solute, solvent & solution in the statement – ‘sodium chloride dissolves in water to give sodium chloride solution’. Define each of the terms in italics.
Give the importance of dissolved minerals & salts.
State the causes of ‘eutrophication’.
Name the process which is responsible for the formation of droplets on the surface of a glass of cold drink. _______
Mountains helps to regulate the temperature of our earth.
State whether the following statement is True or False. If false, write the correct statement.
Rapid growth of industries is one of the causes for water shortage
