16 . Critical Volume : The volume of 1 mole of gat at Tc , Pc .
17 . Super cooled liquids : The liquids which are cooled to a temperature below its freezing point without freezing .
18 . Elastic Collision : The collisions in which no loss of K . E . only there is transfer of energy .
19 . Vapour pressure : The equilibrium pressure by vapour of liquid in a container at given temperature ( T )
20 . At higher altitude : The b . p . of water decreases b / c the atmospheric pressure is less than one atmosphere .
21 . Surface Tension ( V ) : It is force acting per unit length Perpendicular to the line drawn on the surface : ( Nm -1 ) : It decreases with increases in T , it increases with increase in external pressure , b / c of it falling drops of liquid are spherical , liquid in capillary tube rises .
22 . Viscosity ( η ) : It is resistance offered to the flow of liquid due to friction b / w layer of fluids . F n . A . dn dv
23 . Effect of T & P on viscosity : It decreases with increase in T , and increases with increase in P .
24 . Low M . P . & B . P . of molecular liquids is due to low magnitude of molecular interaction energy .