Long Answer TypeState the law of refraction of light that defines the refractive index of a medium with respect to the other. Express it mathematically. How is refractive index of any medium 'A' with respect to a medium 'B' related to the speed of propagation of light in two media A and B? State the name of this constant when one medium is vacuum or air.
The refractive indices of glass and water with respect to vacuum are 3/2 and 4/3 respectively. If the speed of light in glass is 2 × m/s, find the speed of light in (i) vacuum, (ii) water.
What is the difference between the chemical composition of soaps and detergents? State in brief the action of soaps in removing an oily spot from a shirt. Why soaps are not considered suitable for washing where water is hard?
List in tabular form three physical and two chemical properties on the basis of which ethanol and ethanoic acid can be differentiated.
Difference in physical properties of ethanol and ethanoic acid
|
Ethanol |
Ethanoic acid |
|
It is liquid at room temperature. |
It often freezes in winter. |
|
Its melting point is 156 K. |
Its melting point is 290 K. |
|
Its boiling point is 351 K. |
Its boiling point is 391 K. |
Difference in chemical properties of ethanol and ethanoic acid
|
Ethanol |
Ethanoic acid |
|
On reaction with metallic sodium, ethanol releases hydrogen gas. |
Ethanoic acid does not release hydrogen gas on reaction with metallic sodium. |
|
Ethanol does not release carbon dioxide gas on reaction with sodium bicarbonate. |
Carbon dioxide gas is released when ethanoic acid is reacted with sodium bicarbonate. |
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