50.   In which of the following silver is not to be present? [IAS (Pre) 2007]
          (a) Horn silver
          (b) German silver
          (c) Ruby silver
          (d) Lunar caustic
Ans: (b)
51. The metal which forms hydrogen after the reaction of an acid with an alkali is : [MPPCS (Pre) 2009]
          (a) Zinc
          (b) Sodium
          (c) Potasium
          (d) Calcium
Ans: (b)
52. The air is an example of :
          (a) the solution of solid in the gas
          (b) the solution of gas in the gas
          (c) the solution of liquid in the gas
          (d) the solution of liquid in the solid
Ans: (b)
53. The milk is an example of : [BPSC (Pre) 1998]
          (a) Solution
          (b) Collidal solution
          (c) emulsion
          (d) air-solution
Ans: (c)
54. The pH value of a solution is 6 then the hydrogen ion concentration of the solution would be :
          (a) 10-6M
          (b) 10-10M
          (c) 1010M
          (d) 106M
Ans: (a)
55. The hydrogen ion concentration of a solution is 10-4 M then the concentration of hydroxyl ion in it would be :
          (a) 10-4
          (b) 10-14
          (c) 10-10
          (d) 104
Ans: (c)
56. Which of the following is called philosopher"s wool? [IAS (Pre) 2007]
          (a) Zinc bromide
          (b) Zinc nitrate
          (c) Zinc oxide
          (d) Zinc chloride
Ans: (c)
57. In which of the following form alum is used? [NDA 2009]
          (a) as a pain killer
          (b) as a fertilizer
          (c) as an antiseptic
          (d) as a water purifier
Ans: (d)
58. In the process of electrolysis oxidation occurs at :
          (a) cathode
          (b) anode
          (c) both of these
          (d) None of these
Ans: (b)
59. In the process of electrolysis reduction occurs at :
          (a) cathode
          (b) anode
          (c) both of these
          (d) None of these
Ans: (a)
60. Which of the following is used in the form of an electrolyte of the dry cell (battery)? [IAS (Pre) 2007]
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