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प्रश्न
Which of the following 0.10 m aqueous solutions will have the lowest freezing point?
पर्याय
Al2(SO4)3
C5H10O5
KI
C12H22O11
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उत्तर
Al2(SO4)3
Explanation:
Freezing point depression depends on the number of particles in the Van’t Hoff factor (i). Al2(SO4)3 dissociates into 5 ions \[\ce{(2 Al^{3+} + 3 SO^2-_4)}\], producing the maximum number of particles, and hence causes the greatest depression in freezing point.
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संबंधित प्रश्न
When 2.56 g of sulphur was dissolved in 100 g of CS2, the freezing point lowered by 0.383 K. Calculate the formula of sulphur (Sx).
(Kf for CS2 = 3.83 K kg mol−1, Atomic mass of sulphur = 32 g mol−1]
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Read the passage carefully and answer the questions that follow:
| Henna is investigating the melting point of different salt solutions. She makes a salt solution using 10 mL of water with a known mass of NaCl salt. She puts the salt solution into a freezer and leaves it to freeze. She takes the frozen salt solution out of the freezer and measures the temperature when the frozen salt solution melts. She repeats each experiment. |
| S.No | Mass of the salt used in g |
Melting point in °C | |
| Readings Set 1 | Reading Set 2 | ||
| 1 | 0.3 | -1.9 | -1.9 |
| 2 | 0.4 | -2.5 | -2.6 |
| 3 | 0.5 | -3.0 | -5.5 |
| 4 | 0.6 | -3.8 | -3.8 |
| 5 | 0.8 | -5.1 | -5.0 |
| 6 | 1.0 | -6.4 | -6.3 |
Assuming the melting point of pure water as 0°C, answer the following questions:
- One temperature in the second set of results does not fit the pattern. Which temperature is that? Justify your answer.
- Why did Henna collect two sets of results?
- In place of NaCl, if Henna had used glucose, what would have been the melting point of the solution with 0.6 g glucose in it?
OR
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(Kf for benzene = 5.12 K kg mol−1, Atomic mass of sulphur = 32 g mol−1)
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