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प्रश्न
Give reasons: Lakes freeze from top towards bottom.
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उत्तर
During winter, the temperature of lake water keeps on decreasing. Since cold water is heavier, it moves towards the bottom.
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संबंधित प्रश्न
Describe the usefulness of water in biosphere and biological systems.
What properties of water make it useful as a solvent? What types of compound can it (i) dissolve, and (ii) hydrolyse?
Why is it said that-
Water is a universal solvent.
Explain the picture in your own words.
Define the following.
Freezing point
Define the following.
Boiling point
Which of the following equations depict the oxidising nature of \[\ce{H2O2}\]?
If same mass of liquid water and a piece of ice is taken, then why is the density of ice less than that of liquid water?
Give reasons: Ice floats on water.
\[\ce{H2O2}\] is a better oxidising agent than water. Explain.
Melting point, enthalpy of vapourisation and viscosity data of \[\ce{H2O}\] and \[\ce{D2O}\] is given below :
| \[\ce{H, O}\] | \[\ce{D2O}\] | |
| Melting point / K | 373.0 | 374.4 |
| Enthalpy of vapourisation at (373 K)/kJ mol–1 | 40.66 | 41.61 |
| Viscosity/centipoise | 0.8903 | 1.107 |
On the basis of this data explain in which of these liquids intermolecular forces are stronger?
Write two reactions to explain amphoteric nature of water.
The freezing point of water ______ with an increase in pressure.
Pure water boils at ______ °C at one atmospheric pressure.
______ has the highest latent heat of fusion.
Water is circulated around the car engine using the ______ pump and the heat is absorbed.
What are the physical properties of pure water?
Which of the following ion is responsible for the temporary hardness of water?
The density of gold is 19 g/cm3. If 1.9 × 10−4 g of gold is dispersed in one litre of water to give a sol having spherical gold particles of radius 10 nm, the number of gold particles per mm3 of the sol will be ______ × 106.
