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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
Arrange the following:
CaH2, BeH2 and TiH2 in order of increasing electrical conductance.
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.
Sea water is a bad conductor of electricity.
State whether the following statement is true or false.
The substance in which a solute dissolves is called a solvent.
Explain the picture in your own words.
Explain the various properties of water.
Why is the density of seawater more than that of rain water?
Define the following.
Boiling point
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: 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?
Explain why \[\ce{HCl}\] is a gas and \[\ce{HF}\] is a liquid.
Why does water show high boiling point as compared to hydrogen sulphide? Give reasons for your answer.
How will you account for 104.5° bond angle in water?
Pure water boils at ______ °C at one atmospheric pressure.
What is the taste of distilled water & boiled 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.
