CBSE Class 12 · 2024 · SolutionsMultiple Choice

Van't Hoff factor for Na${}_2$SO${}_4\cdot$10H${}_2$O solution, assuming complete ionization, is

(a)(i) Ishan's automobile radiator is filled with 1.0 kg of water. How many grams of ethylene glycol (molar mass = 62 g mol${}^{-1}$) must Ishan add to get the freezing point of the solution lowered to −2.8°C? (K${}_f$ for water = 1.86 K kg mol${}^{-1}$)
(ii) What type of deviation fro …

(b)(i) The boiling point of water at 750 mm Hg pressure is 99.68°C. How much sucrose (molar mass = 342 g mol${}^{-1}$) is to be added to 500 g of water so that it boils at 100°C? (K${}_b$ for water = 0.52 K kg mol${}^{-1}$)
(ii) State Henry's law and write any one application of it.

Which of the following aqueous solutions will have the highest boiling point?

(i) Why is the boiling point of 1 M NaCl solution more than that of 1 M glucose solution?
(ii) A non-volatile solute 'X' (molar mass = 50 g mol${}^{-1}$), when dissolved in 78 g of benzene, reduced its vapour pressure to 90%. Calculate the mass of X dissolved in the solution.
(iii) …

(i) Why is the value of van't Hoff factor for ethanoic acid in benzene close to 0.5?
(ii) Determine the osmotic pressure of a solution prepared by dissolving 2.32 × 10${}^{-2}$ g of K${}_2$SO${}_4$ in 2 L of solution at 25°C, assuming that K${}_2$SO${}_4$ is completely dissociated. (R = 0. …