70.   The catalyst used in the production of ammonia by the Haber"s process is:
         (a) nickel
         (b) iron
         (c) platinum
         (d) molybdenum
Ans: (d)
71. Bronze is often used to make statues and medals whereas brass is used in making utensils, scientific apparatus
         and cartridges. Both brass and bronze are copper containing alloys, yet they differ in their chemical
         composition for additionally containing- [NDA 2011]
         (a) Zinc in brass and tin in bronze
         (b) Chromium in brass and nickel in bronze
         (c) Nickel in brass and tin in bronze
         (d) Iron in brass and nickel in bronze
Ans: (a)
72. When the water vapour is poured on the red heated coke then the mixture of carbon monoxide and hydrogen gas
         is produced which is :
         (a) coal gas
         (b) water gas
         (c) producer gas
         (d) biogas
Ans: (b)
73. The gaseous mixture of carbon monoxide and nitrogen is called:
         (a) coal gas
         (b) water gas
         (c) producer gas
         (d) natural gas
Ans: (c)
74. The main component of the natural gas is:
         (a) methane
         (b) ethane
         (c) propane
         (d) butane
Ans: (a)
75. Which one of the following is a component of tear gas? [SSC Graduate Level (Pre) 2010]
         (a) Ethane
         (b) Ethanol
         (c) Ether
         (d) Chloropicrine
Ans: (d)
76. Which one of the following has the maximum calorific value: [IAS (Pre) 1997]
         (a) hydrogen
         (b) charcoal
         (c) natural gas
         (d) gasoline
Ans: (a)
77. Which one of the following periodic properties of the elements does not exhibit the specific characteristic? [NDA
         2010]
         (a) Atomic size
         (b) Valency
         (c) Radioactivity
         (d) Electron r:egativity
Ans: (c)
78. Which among the following is the correct increasing order of pH found in human body? [CDS 2010]
         (a) Gastric juice, saliva, blood
         (b) Blood, saliva, gastric juice
         (c) Saliva, blood, gastric juice
         (d) Gastric juice, blood, saliva
Ans: (a)
79. The brown coal is:
         (a) peat
         (b) lignite
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