Refer to the solubility curves given in Activity 5.2. If equal masses of hot. Class 9

Refer to the solubility curves given in Activity 5.2. If equal masses of hot. Class 9

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Question 1.

Refer to the solubility curves given in Activity 5.2. If equal masses of hot, saturated solutions of compounds ‘A’ and ‘B’ are cooled from 80 °C to 60 °C, which solution is likely to deposit more solid? Class 9

Answer:

Compound B will deposit more solid. Looking at the solubility curves, Compound B shows a steeper decrease in solubility when cooled from 80°C to 60°C compared to Compound A. Therefore, more of Compound B will crystallise out.

Question 2.

Will there be any change in the size of common salt crystals if the rate of evaporation is increased or decreased? Explain. Class 9

Answer:

Yes. If evaporation rate is increased (fast evaporation), crystals form quickly and are smaller in size. If evaporation rate is decreased (slow evaporation), crystals grow slowly and are larger, well-shaped crystals. This is because slow cooling/evaporation gives particles enough time to arrange themselves in a proper geometric pattern.