- 1(current)
Q. No.Select the correct option based on statements below:
| Assertion (A): | When methyl alcohol is added to water, boiling point of water increases. |
| Reason (R): | When a volatile solute is added to a volatile solvent, elevation in boiling point is observed. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
The unit of Ebullioscopic constant is:
1. K kg mol–1 or K (molality)–1
2. mol kg K–1 or K–1 (molality)
3. kg mol–1 K–1 or K–1 (molality)–1
4. K mol kg–1 or K (molality)
Match the laws/colligative properties given in Column-I with expressions given in Column-II.
| Column-I | Column-II | ||
| A. | Raoult’s law | I. | \(\mathrm{\pi=C R T}\) |
| B. | Osmotic pressure | II. | \(\Delta \mathrm{T}_{\mathrm{f}}=\mathrm{K}_{\mathrm{f}} \mathrm{~m}\) |
| C. | Elevation of boiling point | III. | \(\mathrm{p=x_1 p_1^0+x_2 p_2^0}\) |
| D. | Depression in freezing point | IV. | \(\Delta \mathrm{T}_{\mathrm{b}}=\mathrm{K}_{\mathrm{b}} \mathrm{~m}\) |
Codes:
| A | B | C | D | |
| 1. | I | III | IV | I |
| 2. | I | II | III | IV |
| 3. | I | IV | III | II |
| 4. | III | I | IV | II |
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
| Statement I: | The value of Kf can be calculated by using \( K_{f} \ = \ \frac{R\times M_{1}\times T_{f}^{2}}{1000\times \Delta _{fus}H}\) |
| Statement II: | Unit of Ebullioscopic constant(Kb) is K kg L-1. |
| 1. | Statement I is True, Statement II is False. |
| 2. | Statement I is False, Statement II is True. |
| 3. | Both Statement I and Statement II are True. |
| 4. | Both Statement I and Statement II are False. |
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 |
The incorrect statement among the following is:
| 1. | Units of atmospheric pressure and osmotic pressure are the same. |
| 2. | In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration. |
| 3. | The value of molal depression constant depends on nature of solvent. |
| 4. | Relative lowering of vapour pressure, is a dimensionless quantity. |
(Molal elevation constant for water is 0.52 K kg mol−1 )
1. 128.17 g
2. 121.67 g
3. 125.57 g
4. 116.27 g
A solution that has the highest boiling point among the following is:
1. 1.0 M NaOH
2. 1.0 M Na2SO4
3. 1.0 M NH4NO3
4. 1.0 M KNO3
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Q. No.
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