(iv) P has a fixed composition (a) (i), (ii) and (iii), (b) (i), (ii) and (iv) (c) (ii), (iii) and (iv) (d) (i), (iii) and (iv) Short Answer Questions 10. Suggest separation technique(s) one would need to employ to separate the following mixtures. (a) Mercury and water (b) Potassium chloride and ammonium chloride (c) Common salt, water and sand (d) Kerosene oil, water and salt 11. Which of the tubes in Fig. 2.1 (a) and (b) will be more effective as a condenser in the distillation apparatus? 12. Salt can be recovered from its solution by evaporation. Suggest some other technique for the same? (a) (b)13. The ‘sea-water’ can be classified as a homogeneous as well as heterogeneous mixture. Comment. Fig. 2.1 14. While diluting a solution of salt in water, a student by mistake added acetone (boiling point 56°C). What technique can be employed to get back the acetone? Justify your choice. 15. What would you observe when (a) a saturated solution of potassium chloride prepared at 60°C is allowed to cool to room temperature. (b) an aqueous sugar solution is heated to dryness. (c) a mixture of iron filings and sulphur powder is heated strongly. 16. Explain why particles of a colloidal solution do not settle down when left undisturbed, while in the case of a suspension they do. 17. Smoke and fog both are aerosols. In what way are they different? 18. Classify the following as physical or chemical properties (a) The composition of a sample of steel is: 98% iron, 1.5% carbon and 0.5% other elements. (b) Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas. (c) Metallic sodium is soft enough to be cut with a knife. (d) Most metal oxides form alkalis on interacting with water. (e) When light is passed through water containing a few drops of milk, it shows a bluish tinge. This is due to the ——— of light by milk and the phenomenon is called ——— . This indicates that milk is a ——— solution. EXEMPLAR PROBLEMS 26. Sucrose (sugar) crystals obtained from sugarcane and beetroot are mixed together. Will it be a pure substance or a mixture? Give reasons for the same. 27. Give some examples of Tyndall effect observed in your surroundings? 28. Can we separate alcohol dissolved in water by using a separating funnel? If yes, then describe the procedure. If not, explain. 29. On heating calcium carbonate gets converted into calcium oxide and carbon dioxide. (a) Is this a physical or a chemical change? (b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved. 30. Non metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured. (a) Name a lustrous non-metal. (b) Name a non-metal which exists as a liquid at room temperature. (c) The allotropic form of a non-metal is a good conductor of electricity. Name the allotrope. (d) Name a non-metal which is known to form the largest number of compounds. (e) Name a non-metal other than carbon which shows allotropy. (f) Name a non-metal which is required for combustion. 31. Classify the substances given in Fig. 2.2 into elements and compounds Fig. 2.2 EXEMPLAR PROBLEMS

RELOAD if chapter isn't visible.