(a)  Ammonium chloride and zinc chloride
         (b)  Sodium chloride and calcium chloride
         (c)  Magnesium chloride and zinc chloride
         (d)  Ammonium chloride and calcium chloride
Ans: (a)
61. The iron container (vessel) is galvanized by: [Jharkhand PCS (Pre) 2008]
         (a) Chromium
         (b) Zinc
         (c) Aluminium
         (d) Nickel
Ans: (b)
62. Silver ware turns black after a period of time due to formation of [NDA 2011]
         (a) nitrate coating on silver
         (b) sulphide coating on silver
         (c) chloride coating on silver
         (d) oxide coating on silver
Ans: (b)
63. Which one among the following methods is not effective in removing arsenic from contaminated ground water?
         [NDA, 2011]
         (a) Boiling
         (b) Coagulation adsorption
         (c) Ion exchange
         (d) Reverse osmosis
Ans: (b)
64. Cryolite is an ore of which one of the following metal? [CDS 2008]
         (a) Antimony
         (b) Barium
         (c) Arsenic
         (d) Aluminium
Ans: (d)
65. Usually doctors recommend the foodstuffs which are prepared in the oil with comparison to the vegetable ghee
         because; [Uttrakhand PCS (Pre) 2008]
         (a) oil has unsaturated fats
         (b) oil has saturated fats
         (c) to store the oil is convenient
         (d) oil is cheeper
Ans: (a)
66. Which one of the following pairs of gases mainly cause the explosion in the land mines? [IAS (Pre) 2008]
         (a) H2 and 02
         (b) Oxygen and acetylene
         (c) Methane and air
         (d) Carbondioxide and methane
Ans: (c)
67. The catalyst used in the hydrogenation process of the oils is :
         (a) Fe
         (b) Ni
         (c) Mo
         (d) Pt
Ans: (b)
68. Which of the following is another name of RDX: [IAS (Pre) 2007]
         (a) Cynohydrine
         (b) Deestron
         (c) Cychlohexane
         (d) Cychlonite
Ans: (d)
69. The catalyst used in the production of H2SO4 by the Contact process is/ are:
         (a) pieces (powder) of iron
         (b) pieces (powder) of platinum
         (c) oxide of nitrogen
         (d) nickel
Ans: (b)