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4 LIQUIDS AND SOLIDS eLearn.Punjab

EXERCISE
(QUESTIONS OF LIQUIDS)

Q1. Choose the best answers from the given choices.
(i) London dispersion forces are the only forces present among the

(a) molecules of water in liquid state
(b) atoms of helium in gaseous state at high temperature
(c) molecules of solid iodine.
(d) molecules of hydrogen chloride gas.
(ii) Acetone and chloroform are soluble in each other due to
(a) intermolecular hydrogen bonding (b) ion-dipole interaction
(c) instantaneous dipole (d) all of the above
(iii) NH, shows a maximum boiling point among the hydrides of Vth group elements due to
(a) very small size of nitrogen (b) lone pair of electrons present on nitrogen.
(c) enhanced electronegative character of nitrogen
(d) pyramidal structure of NH3
(iv) When water freezes at 0"C, its density decreases due to
(a) cubic structure of ice (b) empty spaces present in the structure of ice
(c) change of bond lengths (d) change of bond angles
(v) In order to raise the boiling point of water upto 110°C, the external pressure should be
(a) between 760 torr and 1200 torr (b) between 200 torr and 760 torr
(c) 765 torr (d) any value of pressure

Q2. Fill in the blanks with suitable words
(i) The polarizability of noble gases________down the group and results in the increase in
their boiling points.
(ii) ________ is developed in acetone and chloroform when they are mixed together.
(iii) Exceptionally weak_____of HF is due to strong hydrogen bonding present in it.
(iv) The concept of dynamic equilibrium is the ultimate _______of all reversible systems.
(v) DHv of C6H14 should be_____ than that of C2H6.
(vi) During the formation of ice from liquid water there is a______ % increase in volume.
(vii) The rate of increase of vapour pressure of water_______at high temperatures.
(viii) A layer of ice on the surface of water____the water underneath for further heat loss.
(ix) Evaporation is a ________process.
(x) Liquid crystals are used in the display of_________ devices.

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