Shaillee Kaushal is teaching live on Unacademy Plus
XII- 02 Solutions - X
Abnormal colligative properties if the total number of particles of the solute changes in solution, the colligative property should also change accordingly. . When dissociation of an electrolyte takes place i.e, the substance undergoes ionization, the number of particles increase and hence the value of colligative property also increases . When association of substance takes place, a single giant molecule is formed, the number of particles decreases and thus colligative property also decreases
abnormal colligative property Normal colligative property Vant Hofffactor i Pobs A p obs Apnormal P i-ATbobs Tbnormal ATnormal
Suppose 'n' molecules associate to form one giant molecule and o is the degree of association Fore.g O-H..o O...H-O Total number ofparticles in solution ox 1-oc+- rl = 19 i-1 1/n-1 Also Normal molar mass observed molar mass
Relation between osmotic pressure and vapour pressure Thus osmotic pressure is directly proportional to lowering of vapour pressure. Po P Osmotic pressure is proportional to relative lowering of vapour pressure.
Partialpressures of immiscible liquids: PB B PA WA.MB