If 30 grams of KClO₃ is added to 100 grams of water at 0°C, some of the solute remains undissolved. What is the minimum temperature that must be attained to dissolve all the solute?

Question

If 30 grams of KClO₃ is added to 100 grams of water at 0°C, some of the solute remains undissolved. What is the minimum temperature that must be attained to dissolve all the solute??  
A. 30°C  
B. 70°C  
C. 80°C  
D. 100°C

Accepted Answer

Correct Answer: (B)70°C. 
Rationale: The minimum temperature required to dissolve all 30 grams of KClO₃ in 100 g of water is 70°C.Solubility curves graphically represent the maximum amount of solute that can dissolve in a given amount of solvent (usually 100 g of water) at different temperatures. If 30 g of KClO₃ is added to 100 g of water at 0°C and some remains undissolved, it means the solubility at 0°C is less than 30 g/100g. To dissolve all 30 g, the temperature must be raised to the point where the solubility of KClO₃ is at least 30 g/100g. This point is found where a horizontal line at 30 g on the y-axis intersects the KClO₃ solubility curve; the corresponding temperature on the x-axis is the minimum required.A) 30°CAt 30°C, the solubility of KClO₃ is typically less than 30 g/100g water (often around 10-15 g based on common solubility curves). Therefore, at 30°C, not all 30 grams would dissolve; some solid would still remain.B) 70°COn a standard solubility curve for KClO₃, the solubility line crosses the 30 g/100g water mark at approximately 70°C. This means at 70°C, the solution is exactly saturated with 30 g of KClO₃. At any temperature at or above 70°C, the solubility is greater than or equal to 30 g/100g, allowing all the solute to dissolve.C) 80°CAt 80°C, the solubility of KClO₃ is greater than 30 g/100g water, so all the solute would certainly dissolve. However, 80°C is not the minimum temperature required; it is higher than necessary. The question asks for the lowest temperature at which no solid remains.D) 100°CAt 100°C, the solubility is even higher, and dissolution would occur rapidly. Again, this temperature is sufficient but not the minimum required to achieve the goal.Conclusion:To find the minimum temperature to dissolve a specific mass of solute, one must reference the solubility curve for that substance. The minimum temperature corresponds precisely to the point where the solubility equals the mass of solute present per 100 g of solvent. For 30 g of KClO₃ in 100 g of water, this intersection occurs at 70°C.

If 30 grams of KClO₃ is added to 100 grams of water at 0°C, some of the solute remains undissolved. What is the minimum temperature that must be attained to dissolve all the solute?

A
30°C

B
70°C

C
80°C

D
100°C

The minimum temperature required to dissolve all 30 grams of KClO₃ in 100 g of water is 70°C.

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If 30 grams of KClO₃ is added to 100 grams of water at 0°C, some of the solute remains undissolved. What is the minimum temperature that must be attained to dissolve all the solute?

A 30°C B 70°C C 80°C D 100°C

The minimum temperature required to dissolve all 30 grams of KClO₃ in 100 g of water is 70°C.

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Related Questions

A
30°C

B
70°C

C
80°C

D
100°C