Give reasons for the following :
(a) Measurement of osmotic pressure method is preferred for the determination of molar masses of macromolecules such as proteins and polymers .
(b) Aquatic animals are more comfortable in cold water than in warm water .
(c) Elevation of boiling point of `1M KCl` solution is nearly double than that of 1 M sugar solution.

Explanation

Measurement of osmotic pressure method is preferred for the determination of molar masses of macromolecules such as proteins and polymers because this method has the advantage that is use molarities instead of molalities . Secondly , the changes observed in these properties are very small . On the other hand , osmotic pressures of the order of `10^(-3)` atm . can be easily measured in term of mm.
(b) Aquatic species need dissolved oxygen for breathing . As solubility of gases decreases with increase of temperature , less oxygen is available in summer in the lakes . Hence , they feel more comfortable in winter when the solubility is high .
(c) KCl , being an electrolyte , dissociates almost completely to give `K^(+)` and `Cl^(-)` ions whereas glucose being non-electrolyte , does not dissociate . Hence , number of particles in 1M KCl solution is nearly double than in 1M sugar solution . Elevation of boiling point , being a colligative property is therefore , nearly twice for KCl solution than for glucose solution of same molarity .