Explore topic-wise InterviewSolutions in .

(1) Consider V dm³ of a solution in which n₁ moles of a solvent contains n₂ moles of a nonvolatile solute at absolute temperature T.

(2) The osmotic pressure, n of a solution is given by,

π = \(\frac{nRT}{V}\)

R is gas constant having value 0.08206 dm³ atm K^-1 mol^-1 (OR L atm K^-1 mol^-1). Since concentration, C of a solution is in mol dm^-3 or molarity is,

C = \(\frac{n}{V}\) mol dm^-3 or M 

∴ π = CRT

(If concentration C is expressed in mol^-3 m and R = 8.314 J K^-1 mol^-1, then π will be in SI units, pascals or Nm^-2)

(1) Permeable membrane : A membrane which allows free transfer of the solute molecules from a solution of a higher concentration to a solution of a lower concentration through it is called a permeable membrane and the transfer is called diffusion, e.g., a membrane of a paper.

(2) Semipermeable membrane : A membrane which allows free passage of only the solvent molecules but not the large solute molecules or ions of large molecular mass from a solution of a lower concentration (or a pure solvent) to a solution of higher concentration through it, is called a semi-permeable membrane, 

e.g., parchment paper, complex like Cu₂[Fe(CN)₆], etc.

Option : (b) 0.1 M NaNO₃

Option : (d) 1 mole of solute in one kg of solvent

Option : (c) ebullioscopy

\(\pi = \frac{W_BRT}{M_BV}\)

\(M_B= \frac{W_BRT}{\pi V}\)

= \(\frac{1.26\,g\,\times\,0.083\,L\,bar\,K^{-1}\,mol^{-1}\times300\,K}{2.57\times10^{-3}\,bar\times0.2\,L}\)

= 61,039 g mol^-1

Option : (c) lower than vapour pressure of pure solvent.

ppm (parts per million)

(1) Homogeneous solution : A solution in which solute and solvent form uniform homogeneous one phase due to attraction between their molecules/particles is called homogeneous solution. 

E.g. A solution of NaCl or sugar.

(2) Heterogeneous solution : A solution consisting of two or more phases is called a heterogeneous solution. 

E.g. A colloidal solution of starch.

It is the ratio of normal molecular mass to observed molecular mass . H is denoted as ‘i’ 

i = normal m.m / observed m.m 

= no. of particles after association or dissociation / no. of particles before

M = P x d x 10/M.M

Solution of hydrogen in palladium.

There is strong hydrogen bonding in alcohol molecules as well as water molecules. The intermolecular forces both in alcohol and water are H-bonds. 

When alcohol and water are mixed, they form solution because of formation of H-bonds between alcohol and H₂O molecules hut these interactions are weaker and less extensive than those in pure water. 

Hence, they show positive deviation from ideal behaviour.

Positive deviation from ideal behavior.

 In alcohol and water solution interaction between alcohol and water molecules show inter molecular hydrogen bonding but it is weaker than water – water and alcohol – alcohol hydrogen bonding. 

Henry’s Law states that the solubility of a gas in liquid is directly proportional to the partial pressure of the gas.  

Applications:- 

(1) In deep sea diving. 

(2) In aerated water e.g. soft drinks. 

There is strong hydrogen bonding in alcohol molecules as well as water molecules. On mixing the molecular interactions are weekend. Hence, they show positive deviations from ideal behaviour. AS a result, the solution will have higher vapour pressure and lower boiling point than that of water and alcohol.

Henry’s law states that at constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas. 

Applications: It is used

• in the production of carbonated beverages
• in the deep sea diving
• in the function of lungs.