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प्रश्न
Describe the usefulness of water in biosphere and biological systems.
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उत्तर
Water is essential for all forms of life. It constitutes around 65% of the human body and 95% of plants. Water plays an important role in the biosphere owing to its high specific heat, thermal conductivity, surface tension, dipole moment, and dielectric constant.
The high heat of vapourization and heat of capacity of water helps in moderating the climate and body temperature of all living beings.
It acts as a carrier of various nutrients required by plants and animals for various metabolic reactions.
संबंधित प्रश्न
Among NH3, H2O and HF, which would you expect to have highest magnitude of hydrogen bonding and why?
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-
There is no alternative to water for cleaning purposes.
Why is the density of seawater more than that of rain water?
Which of the following equations depict the oxidising nature of \[\ce{H2O2}\]?
Some of the properties of water are described below. Which of them is/are not correct?
(i) Water is known to be a universal solvent.
(ii) Hydrogen bonding is present to a large extent in liquid water.
(iii) There is no hydrogen bonding in the frozen state of water.
(iv) Frozen water is heavier than liquid water.
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: Lakes freeze from top towards bottom.
Give reasons: Ice floats on water.
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.
Freezing of water will cause an ______ is the volume.
One gram of water requires ______ of heat to raise its temperature by l°C.
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.
The water having more dissolved O2 is ______.
