I. Evaporation
II. Crystallization
Select the correct answer using the code given below.
Separating Non-Volatile Solids from Solutions
The question asks for methods to separate a non-volatile solid solute from a solution. Let's examine the given processes:
Evaporation
Evaporation is a process where a liquid solvent turns into a gas (vapor) and escapes from the solution. If the solid solute is non-volatile (meaning it does not easily turn into vapor at the boiling point of the solvent), it will remain behind after the solvent evaporates. This method is effective for recovering the solute, although it might not yield a pure product if impurities are also non-volatile.
- Process: Heating the solution to vaporize the solvent.
- Result: The non-volatile solid solute is left behind.
Crystallization
Crystallization is a separation technique used to obtain pure solid crystals from a solution. It often involves cooling a saturated solution or evaporating some of the solvent. As the solution cools or becomes more concentrated, the solubility of the solid solute decreases, causing it to form crystals. This method is excellent for purifying the solid solute because impurities often remain dissolved in the mother liquor.
- Process: Changing conditions (e.g., cooling, solvent evaporation) to reduce solute solubility.
- Result: Pure solid solute crystallizes out of the solution.
Conclusion
Both evaporation and crystallization are suitable methods for separating a non-volatile solid solute from a solution. Evaporation primarily removes the solvent, leaving the solute behind, while crystallization yields purified solid crystals of the solute.
Therefore, both processes I (Evaporation) and II (Crystallization) can be used.
Important Questions from Mixture Problems (Notes)
- A has a container containing 60 litres of pure milk. He takes out 4 litres of milk and replaces it with the same quantity of water. He sells this mixture to B. B sells 30 litres of the mixture and added 5 litres of water in the remaining mixture. The ratio of milk to water in the remaining mixture is:
- How many liters of water should be added to a 30-liter mixture containing milk and water in the ratio 7:3 such that the resultant mixture has 40% water in it?
- A $595$ litre of mixture contains milk and water in the ratio $17:18$. How much milk must be added to the mixture so that it contains milk and water in the proportion of $3:2$?
- Alloy A is formed by mixing iron (Fe) and nickel (Ni) in the ratio 3:4, while alloy B is formed by mixing Fe and Ni in the ratio 9:5. If equal quantities of alloys A and B are melted together to form a new alloy C, what will be the ratio of Fe to Ni in the alloy C?
Suppose a tap mixes hot water and cold water in a ratio that depends linearly on the proportion of opening. Water out of the tap has temperature 40°C when the tap is half-open, and 30°C when it is three-fourths open. To get water at 50°C, the tap should be_______________.
