Free NCERT Solutions For Class 12 Chemistry Chapter 2: Solutions Free PDF Download

INTEX QUESTIONS

Question 1:
Calculate the mass percentage of benzene (C6H6) and carbon tetrachloride (CCl4) if 22 g of benzene is dissolved in 122 g of carbon tetrachloride.

Question 2:
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.

Question 4:
Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25 molal aqueous solution

Question 5:
Calculate (a) molality (b) molarity and (c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g mL-1

Question 6:
H2S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H2S in water at STP is 0.195 m, calculate Henry’s law constant.

Question 8:
The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K. Find out the composition of the liquid mixture if total vapour pressure is 600 mm Hg. Also find the composition of the vapour phase.

Question 9:
Vapour pressure of pure water at 298 K is 23.8 mm Hg. 50 g of urea (NH2CONH2) is dissolved in 850 g of water. Calculate the vapour pressure of water for this solution and its relative lowering.

Question 10:
Boiling point of water at 750 mm Hg is 99.63C. How much sucrose is to be added to 500 g of water such that it boils at 100C.

NCERT Exercise

Question 1:
Define the term solution. How many types of solutions are formed? Write briefly about each typewith an example.

Question 3:
Define the following terms:
(i) Mole fraction
(ii) Molality
(iii) Molarity
(iv) Mass percentage

Question 4:
Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in aqueous solution. What should be the molarity of such a sample of the acid if the density of the solution is 1.504 g mL-1 ?

Question 5:
A solution of glucose in water is labelled as 10% w/w, that would be the molality and molefraction of each component in the solution? If the density of solution is 1.2g mL-1then what shall be the molarity of the solution?

Question 6:
How many mL of 0.1 M HCl are required to react completely with 1 g mixture of Na2CO3 and NaHCO3 containing equimolar amounts of both?

Question 7:
A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution

Question 9:
A sample of drinking water was found to be severely contaminated with chloroform (CHCl3), supposed to be a carcinogen. The level of contamination was 15 ppm (by mass).
(i) express this in percent by mass.
(ii) determine the molality of chloroform in water sample.

Question 11:
Why do gases always tend to be less soluble in liquids as the temperature is raised?

Question 12:
State Henry’s law and mention some important applications.

Question 15:
An aqueous solution of 2% non-volatile solute exerts a pressure of 1.004 bar at the normal boiling point of the solvent. What is the molar mass of the solute?

Question 16:
Heptane and octane form an ideal solution. At 373 K, the vapour pressure of the two liquid components 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure of a mixture
of 26.0 g of heptane and 35.0 g of octane?

Question 17:
The vapour pressure of water is 12.3 kPa at 300 K. Calculate vapour pressure of 1 molal solution of a non-volatile solute in it

Question 19:
A solution containing 30g of non-volatile solute exactly in 90 g of water has a vapour pressure of 2.8 kPa at 298 K. Further, 18g of water is then added to the solution and the new of vapour pressure becomes 2.9 kPa at 298 K. Calculate
(i) molar mass of the solute
(ii) vapour pressure of water at 298 K.

Question 20:
A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15K.

Question 23:
Suggest the most important type of intermolecular attractive interaction in the following pairs:
(i) n-hexane and n-octane
(ii) I2 and CCl4.
(iii) NaClO4 and water
(iv) methanol and acetone
(v) acetonitrile (CH3CN) and acetone (C3H6O)

Question 25:
Amongst the following compounds, identify which are insoluble, partially soluble and highly soluble in water
(i) phenol
(ii) toluene
(iii) formic acid
(iv) ethylene glycol
(v) chloroform
(vi) Pentanol

Question 31:
The depression in freezing point of water observed for the same amount of acetic acid, trichloroacetic acid and trifluoroacetic acid increases in the order given above. Explain briefly.

Question 34:
Vapour pressure of water at 293 K is 17.535 mm Hg. Calculate the vapour pressure of water at 293 K when 25 g of glucose is dissolved in 450 g of water.

Question 39:
The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approximate proportion of 20% is to 79% by volume at 298 K. The water is in equilibrium with air at a pressure of 10 atm. At 298 K if the Henry’s law constants for oxygen and nitrogen are 3.30 × 107 mm and 6.51 × 107 mm respectively, calculate the composition of these gases in water