Solutions - Intext Questions and Answer - class 12 chemistry

Solution of NCERT In Text Questions

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Question - 2.1 - Calculate the mass percentage of benzene (C6 H 6) and carbon tetrachloride (CCl 4) if 22 g of benzene is dissolved in 122 g of carbon tetrachloride.

Question - 2.2 - Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.

Question - 2.3 - Calculate the molarity of each of the following solutions:

(a) 30 g of Co(NO 3) 2. 6H2 O in 4.3 L of solution

(b) 30 mL of 0.5 M H 2SO4 diluted to 500 mL.

Question - 2.4 - Calculate the mass of urea (NH2 CONH 2) required in making 2.5 kg of 0.25 molal aqueous solution.

Question - 2.5 - 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 - 2.6 - H 2S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H2 S in water at STP is 0.195 m, calculate Henry❜s law constant.

Question - 2.7 - Henry❜s law constant for CO2 in water is 1.67x108 Pa at 298 K. Calculate the quantity of CO2 in 500 mL of soda water when packed under 2.5 atm CO 2 pressure at 298 K.

Question - 2.8 - 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 - 2.9 - Vapour pressure of pure water at 298 K is 23.8 mm Hg. 50 g of urea (NH2 CONH2 ) is dissolved in 850 g of water. Calculate the vapour pressure of water for this solution and its relative lowering.

Question - 2.10 - 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.

Question - 2.11 - Calculate the mass of ascorbic acid (Vitamin C, C6 H8 O 6) to be dissolved in 75 g of acetic acid to lower its melting point by 1.5°C. K f = 3.9 K kg mol-1.

Question - 2.12 - Calculate the osmotic pressure in pascals exerted by a solution prepared by dissolving 1.0 g of polymer of molar mass 185,000 in 450 mL of water at 37°C.