Short Answer TypeExplain the following:
(i) Drops of liquid assume a spherical shape.
(ii) The level of mercury in a capillary tube is lower than the level outside when a capillary tube is inserted in mercury.
Liquid that wets glass rises in a capillary tube or oil rises in the wick of an oil Jamp. Explain.
Long Answer TypeExplain the following:
(i) The boiling point of water (373 K) is abnormally high when compared to that of H2S (211·2K).
(ii) Liquids like ether and acetone are kept in cool places.
(iii) Tea or coffee is sipped from a saucer when it is quite hot.
Explain briefly the term viscosity. Define coefficient of viscosity. What are its units?
Viscosity. The viscosity of the liquid is its property by virtue of which it tends to oppose the relative motion between two adjacent layers. In other words, all liquids exhibit resistance to flow. It is clear that the resistance to flow is governed by intermolecular forces. If the intermolecular forces are strong, there is greater resistance to flow i.e. viscosity has a high value. For example, glycerol, honey and concentrated H2SO4 are highly viscous due to stronger intermolecular attractive forces.
The coefficient of viscosity: It has been found that the force of friction (F) per unit area is directly proportional to the difference in velocity v of the two adjacent layers and inversely proportional to the distance x, between them
The coefficient of viscosity may be defined as the force in newton per square metre required to maintain a difference of velocity of one metre per second, between two parallel layers of the liquid at a distance of one metre from each other. Unit. It is measured in kg m–1 s–1.
Short Answer TypeWhich one in each of the following pairs is more viscous?
(i) Coconut oil, castor oil
(ii) glyercine, kerosene
(iii) soft drink, aerated water (soda water)?
Long Answer TypeWhat is the effect of temperature on:
(i) density
(ii) surface tension
(iii) viscosity
(iv) the vapour pressure of a liquid?
Short Answer TypeWhat is the effect of pressure on:
(i) volume
(ii) boiling point
(iii) viscosity of a liquid?
Long Answer TypeShort Answer Type
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