CBSE Guess > Papers > Important Questions > Class IX > 2009 > Science > Science By : Mr M. p. Keshri
CBSE CLASS I X
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Q. 61. What is separating funnel ? Write its different uses.
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Q. 62. What is sublimation ? Describe the process used to separate the common salt and ammonium chloride from their mixture.
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Q. 63. What is distillation ? Explain the process.
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Q. 64. Write the type of mixture that can be separated by distillation.
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Q. 65. How a mixture of ethyl alcohol ( boiling point 78ºC ) and water ( boiling point 100ºC ) is separated. Write the process with diagram.
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Q. 66. How will you separate a mixture containing kerosene and petrol ( difference in their boiling points is more than 25ºC ), which are miscible with each other ?
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Q. 67. A mixture of toluene and acetone is distilled in a distillation flask and it is found that the temperature becomes constant at 56ºC for some time the residual liquid left is toluene. On continuing the heating, temperature becomes constant at 80ºC. Now answer the following questions :
(i) Write the boiling points of acetone and toluene.
(ii) Why is it possible to separate acetone from toluene ?
(iii) Temperature remains constant at 56ºC even though heating is continued. Why ?
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Q. 68. State the advantage of distillation over evaporation.
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Q. 69. Define chromatography. Write its uses.
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Q.70. What is blue/black ink ?
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Q. 71. How will you show that the dye used in blue/black ink is a mixture of two or more components.
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Q. 72. State the important criteria to use chromatography for separating components of a mixture.
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Q. 73. What is a fractional column ? What is advantage of it ?
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Q.74. State important industrial applications of fractional distillation.
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Q.75. A mixture of liquid ‘A’ with boiling point 80ºCand other ‘B’ with boiling point 90ºCis given. How will they be separated ?
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Q. 76. How the constituents of air is separated ?
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Q. 77. Boiling points of oxygen, argon and nitrogen are – 182ºC, - 186ºC and – 196ºC respectively. Answer the following questions :
(i) arrange the gases in descending value of their boiling points.
(ii) which gas condenses first when air is cooled ?
(iii) when liquid air is boiled, which gas is obtained first ?
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Q. 78. Diesel oil, kerosene, petrol and petroleum ether are fractions of a cruide oil. Their boiling points ranges as 525 – 670 K, 453 – 550 K, 343 – 473 Kand 303 – 363 Krespectively. When the cruide oil is heated, arrange the fractions in the order collected in the distillate.
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Q. 79. What type of mixtures are separated by the technique of crystallization ?
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Q. 80. How will you obtain pure solid substance from its impure sample ? Write the process taking alum as an example.
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Q. 81. State the advantages and disadvantages of crystallization over evaporation.
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Q. 82. What is decantation ? Write the process of decantation.
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Q. 83. Write the method of separation of camphor from sodium chloride.
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Q. 84. How a mixture of sand, water, and mustard oil is separated ?
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Q. 85. Name the technique to separate :
(i)Butter from curd.
(ii) Camphor from salt.
(iii) Fine insoluble particles suspended in liquid.
(iv) A solid dissolved in a liquid.
(v) A sublimable solid mixed with other solid.
(vi) Salt from sea water.
(vii) Three solid substances soluble in a mixture of solvent.
(viii) Two immiscible liquids.
(ix) Two miscible liquids having a difference of 10ºC in their boiling points.
(x) Mixture of helium and nitrogen gas.
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Q.86. Define chromatography. State its advantages over other methods of separation.
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Q. 87. State the principle of chromatography. Name different types of chromatography commonly used.
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Q. 88. Define physical change and chemical change.
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Q. 89. Give reason for the following :
(i) Ripening of a fruit is a chemical change.
(ii) Crystallization is a physical change.
(iii) Formation of curd from milk is a chemical change.
(iv) Separation of gases from air is a physical change.
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Q. 90. Which of the following is a physical change ? Explain with reason.
(i) Hydrogen and oxygen are formed on passing electric current through water.
(ii) A bulb glows on passing an electric current through it.
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Paper By Mr. M. P. Keshari [ For Further Enquiry 09434150289]
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