When 20 g of naphthoic acid (C11H8O2) is dissolved in 50 g of benzene , a freezing point depression
of 2 K is observed. what is the Van’t Hoff factor (i)?
(Kf = 1.72 K kg mol–1)
1. | 0.5 | 2. | 1 |
3. | 2 | 4. | 3 |
The Henry's law constant for the solubility of N2 gas in water at 298 K is 1.0 × 105 atm. The mole fraction of N2 in air is 0.8. The number of moles of N2 formed from air dissolved in 10 moles of water at 298 K and 5 atm pressure is-
1. | 4.0 × 10–4 mol | 2. | 4.0 × 10–5 mol |
3. | 5.0 × 10–4 mol | 4. | 4.0 × 10–6 mol |
If the relative decrease in vapour pressure is 0.4 for a solution containing 1 mol NaCl in 3 mol of , then percentage ionisation of NaCl will be -
1. 60%
2. 80%
3. 40%
4. 100%
Aqueous solutions of 0.004 M Na2SO4 and 0.01 M Glucose are isotonic. The degree of dissociation of Na2SO4 is-
1. 25%
2. 60%
3. 75%
4. 85%
A 500 g toothpaste sample has 0.4 g fluoride concentration. The fluoride concentration in terms of ppm will be -
1. | 200 ppm | 2. | 400 ppm |
3. | 500 ppm | 4. | 800 ppm |
The correct statement regarding a solution of two components A and B exhibiting positive deviation from ideal behaviour is :
1. | Intermolecular attractive force between A-A and B-B are stronger than those between A-B |
2. | ∆mixH = 0 at constant T and P |
3. | ∆mixV = 0 at constant T and P |
4. | Intermolecular attractive forces between A-A and B-B are equal to those between A-B |
The mixture among the following that forms maximum boiling azeotrope is:
1. | Heptane + Octane | 2. | Water + Nitric acid |
3. | Ethanol + Water | 4. | Acetone + Carbon disulphide |
For an ideal solution, the correct option is:
1. at constant T and P
2. at constant T and P
3. at constant T and P
4. at constant T and P
During osmosis, the flow of water through a semi-permeable membrane is:
1. | From a solution having higher concentration only. |
2. | From both sides of the semi-permeable membrane with equal flow rates. |
3. | From both sides of the semi-permeable membrane with unequal flow rates. |
4. | From a solution having lower concentration only. |
1.00 g of non-electrolyte solute (molar mass 250 g mol-1) was dissolved in 51.2 g of benzene. If the freezing point depression constant, Kf of benzene is 5.12 mol-1 kg K, the freezing point of benzene will be lowered by:
1. 0.4 K
2. 0.3 K
3. 0.5 K
4. 0.2 K