Q. No.The incorrect statement among the following for an ideal solution is:
1. \(\Delta H_{\text{Mix}}=0\)
2. \(\Delta U_{\text{Mix}}=0\)
3. \(\Delta P=P_{\text{obs.}}-P_{\text{(Calculated by Raoult's law)}}=0\)
4. \(\Delta G_{\text{Mix}}=0\)
Consider the following statements about the composition of the vapour over an ideal 1:1 molar mixture of benzene and toluene. The correct statement is:
Assume that the temperature is constant at 25 oC.
(Given, vapour pressure data at 25 °C, benzene = 12.8 kPa, toluene = 3.85 kPa)
| 1. | The vapour will contain a higher percentage of toluene. |
| 2. | The vapour will contain equal amounts of benzene and toluene. |
| 3. | Not enough information is given to make a prediction. |
| 4. | The vapour will contain a higher percentage of benzene. |
1. \(\Delta H_\text{mix}\)
2. \(\Delta S_\text{mix}\)
3. \(\Delta V_\text{mix}\)
4. \(\Delta P=P_{\text{observed}}-P_{\text{Raoult}}\)
The boiling point of 0.2 mol kg–1 solution of X in water is greater than the equimolal solution of Y in water. The correct statement in this case is:
| 1. | X is undergoing dissociation in water. |
| 2. | Molecular mass of X is greater than the molecular mass of Y. |
| 3. | Molecular mass of X is less than the molecular mass of Y. |
| 4. | Y is undergoing dissociation in water while X undergoes no change. |
The electrolyte having the same value of Van't Hoff factor (i) as that of Al2(SO4)3 (if all are 100% ionized) is:
1. K2SO4
2. K3[Fe(CN)6]
3. Al(NO3)3
4. K4[Fe(CN)6]
The largest freezing point depression among the following 0.10 m solutions is shown by:
| 1. | \(\mathrm{KCl}\) | 2. | \(\mathrm{C_6H_{12}O_6}\) |
| 3. | \(\mathrm{Al}_2(\mathrm{SO_4})_3\) | 4. | \(\mathrm{K_2SO_4}\) |
pA and pB are the vapour pressure of pure liquid components, A and B, respectively of an ideal binary solution.
If XA represents the mole fraction of component A, the total pressure of the solution will be:
1. pA + XA (pB-pA)
2. pA + XA (pA-pB)
3. pB + XA (pB-pA)
4. pB + XA (pA-pB)
The freezing point depression constant for water is 1.86 oC m-1. If 5.00 g Na2SO4 is dissolved in 45.0 g H2O, the freezing point is changed by -3.82 oC. The van’t Hoff factor for Na2SO4 is:
| 1. | 2.63 | 2. | 3.11 |
| 3. | 0.381 | 4. | 2.05 |
The van’t Hoff factor, i, for a compound that undergoes
dissociation and association in a solvent is, respectively:
1. Less than one and less than one.
2. Greater than one and less than one.
3. Greater than one and greater than one.
4. Less than one and greater than one.
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