Separation Techniques - Evaporation, Filtration, and Distillation - UNSOLVED PRACTICE SET

Q7. Explain the principle of evaporation. Name one mixture from your daily life that can be separated by this method.

Q8. What is filtration? Draw a simple labelled diagram of the filtration process and identify the filtrate and residue when separating sand from water.

Q9. Your mother separates cream from milk by leaving it undisturbed for a few hours. Is this evaporation, filtration, or something else? Explain the principle behind this separation.

Q10. Differentiate between simple distillation and fractional distillation. Give one example where each is used.

Q11. Why can't we use filtration to separate salt from salt water? What method should be used instead, and why?

Q12. A student wants to separate a mixture of alcohol (boiling point 78°C) and water (boiling point 100°C). Which separation technique should he use? Explain the process step by step.

Q13. Describe the process of simple distillation with a labelled diagram. Explain how it is used to separate a mixture of salt and water. What are the advantages of distillation over evaporation for obtaining pure water?

Q14. A farmer has a mixture of sand, salt, and iron filings. Describe a step-by-step method to separate all three components completely. Name the principle behind each separation step and specify what is recovered at each stage.

Q15. "Different separation techniques are chosen based on the properties of the components in a mixture." Discuss this statement by explaining how the following properties determine the choice of separation technique: (i) solubility, (ii) boiling point, (iii) particle size, and (iv) magnetic properties. Give one example for each.

Q16. A student has a 300 g mixture containing sand and salt in the ratio 2:1 by mass.

(a) Calculate the mass of sand and salt in the mixture.

(b) The student adds water to dissolve the salt, filters the mixture, and then evaporates the filtrate. Calculate the mass of salt recovered if the process is 90% efficient.

(c) What mass of sand will be collected as residue?

(d) If the student had used 200 mL of water to dissolve the salt, what was the mass percentage of salt in the solution before filtration? (Assume density of water = 1 g/mL)

Q17. In a distillation experiment, a mixture of 200 mL of ethanol (density 0.79 g/mL, boiling point 78°C) and 300 mL of water (density 1.0 g/mL, boiling point 100°C) is heated.

(a) Calculate the total mass of the mixture.

(b) Calculate the mass percentage of ethanol in the mixture.

(c) At what temperature will the distillation first begin? Explain.

(d) If 100 mL of ethanol is collected as distillate, what is the percentage recovery of ethanol?

Q18. A village water supply contains suspended particles, dissolved salts, and bacteria. The village panchayat wants to set up a water purification system.

(a) Suggest a sequence of separation/purification techniques to obtain clean drinking water from this supply.

(b) If the village produces 1000 litres of raw water per day and the filtration system removes 95% of suspended particles, calculate the mass of suspended particles removed daily if the raw water contains 0.5 g of suspended particles per litre.

(c) After filtration, the water is distilled. If the distillation process is 80% efficient, how much pure water is obtained from 1000 litres of filtered water?

(d) Why is distillation preferred over simple boiling for obtaining drinking water?