0.6 mL of acetic acid (CH3COOH), having density 1.06 g mL–1, is dissolved in 1 litre of water. The depression in freezing point observed for this strength of acid was 0.0205°C. The value of van’t Hoff factor and the dissociation constant of acid are respectively:
1. 1.041; 1.86 × 10–5
2. 2.073; 1.86 × 10–5
3. 0.091; 1.76 × 10–5
4. 1.041; 1.76 × 10–5
2 g of benzoic acid (C6H5COOH) dissolved in 25 g of benzene shows a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.9 K kg mol–1. The percentage association of acid if it forms dimer in solution is:
1. 98.5%
2. 99.2 %
3. 97.5 %
4. 95.2 %
200 cm3 of an aqueous solution of a protein contains 1.26 g of the protein. The osmotic pressure of such a solution at 300 K is found to be 2.57 × 10–3 bar. The molar mass of the protein is:
1. | 61,022 g mol–1 |
2. | 65,042 g mol–1 |
3. | 68,012 g mol–1 |
4. | 57,012 g mol–1 |
1.00 g of a non-electrolyte solute dissolved in 50 g of benzene lowered the freezing point of benzene by 0.40 K. The freezing point depression constant of benzene is 5.12 K kg mol–1. The molar mass of the solute is:
1. | 245 g mol–1 |
2. | 256 g mol–1 |
3. | 264 g mol–1 |
4. | 274 g mol–1 |
45 g of ethylene glycol (C2H6O2) is mixed with 600 g of water. The freezing point of the solution is:
1. 268.15 K
2. 270.95 K
3. 272.75 K
4. 267.15 K
The boiling point of benzene is 353.23 K. When 1.80 g of a non-volatile solute was dissolved in 90 g of benzene, the boiling point is raised to 354.11 K. The molar mass of the solute is:
Kb for benzene is 2.53 K kg mol–1
1. 55 g mol–1
2. 64 g mol–1
3. 58 g mol–1
4. 68 g mol–1
18 g of glucose, C6H12O6, is dissolved in 1 kg of water in a saucepan. The temperature at which water boil at 1.013 bar is-
(Kb for water is 0.52 K kg mol-1)
1. 383.202 K
2. 373.202 K
3. 363.202 K
4. 393.202 K
The vapour pressure of pure benzene at a certain temperature is 0.850 bar. A non-volatile, non-electrolyte solid weighing 0.5 g is added to 39.0 g of benzene (molar mass 78 g mol–1). Vapour pressure of the solution, then, is 0.845 bar. The molar mass of the solid substance is:
1. | 150 g mol–1
|
2. | 180 g mol–1
|
3. | 170 g mol–1
|
4. | 160 g mol–1 |
If N2 gas is bubbled through water at 293 K, how many millimoles of N2 gas would dissolve in 1 litre of water?
(Partial pressure of nitrogen = 0.987 bar, Henry’s law constant for N2 at 293 K = 76.48 kbar).
1. 0.716 mmol
2. 0.616 mmol
3. 0.726 mmol
4. 0.516 mmol