Problem 91
At high altitudes, water boils at a lower temperature because (a) the atmospheric pressure is high at high altitudes (b) the viscosity of water is reduced at high altitudes (c) the atmospheric pressure is low at high altitudes (d) the surface tension of water is reduced at high altitudes.
Problem 93
Which of the following phenomena does not involve surface tension? (a) Mercury drops acquire spherical shape. (b) Liquids tend to rise in the capillary. (c) A liquid flows over a fixed surface. (d) Moist soil grains are pulled together.
Problem 95
Which of the following has highest surface tension? (a) Water (b) Soap solution in water (c) Detergent solution in water (d) Glycerol in water
Problem 96
I is surface molecule whereas II is interior molecule. Choose the correct one. (a) I results net attraction into the liquid. (b) II are attracted in all directions. (c) Both (a) and (b). (d) Neither (a) nor (b).
Problem 97
Which of the following is not a correct expression regarding the units of coefficient of viscosity? (a) dyne \(\mathrm{cm}^{-2}\) s (b) dyne \(\mathrm{cm}^{2} \mathrm{~s}^{-1}\) (c) \(\mathrm{N} \mathrm{m}^{-2} \mathrm{~s}\) (d) \(\mathrm{Pa} \boldsymbol{s}\)
Problem 98
Mark the correct statement for viscosity. (a) Greater the viscosity, more slowly the liquid flows. (b) Viscosity increases with increase in temperature, (c) Hydrogen bonding and van der Waals forces decrease the viscosity. (d) Viscosity is the measure of ease with which a liquid flows.
Problem 100
Pick out the wrong statement(s). (i) Vapour pressure of a liquid is the measure of the strength of intermolecular attractive forces. (ii) Surface tension of a liquid acts perpendicular to the surface of the liquid. (iii) Vapour pressure of all liquids is same at their freezing points. (iv) Liquids with stronger intermolecular attractive forces are more viscous than those with weaker intermolecular force. (a) (ii), (iii) and (iv) (b) (ii) and (iii) (c) (i), (ii) and (iii) (d) (iii) only
