(b) Calcium oxide
         (c) Calcium carbonate
         (d) Calcium sulphate
Ans: (c)
100. Which one of the following is a transition metal? [NDA 2010]
         (a) Aluminium
         (b) Manganese
         (c) Magnesium
         (d) Calcium
Ans: (b)
101. On rusting in the iron: [MPPCS 1991]
         (a) its wt. is increased
         (b) its wt. is decreased
         (c) no changes take place
         (d) its wt. changes
Ans: (a)
102. Which one of the following element is mixed up in making steel which can resist high temperature and which has
         high level hardness:
         (a) aluminium
         (b) chromium
         (c) nickel
         (d) tungsten
Ans: (b)
103. Human stomach produces acid "X" which helps in digestion of food. Acid "X" is-
         (a) Acetic acid
         (b) Methanoic acid
         (c) Hydrochloric acid
         (d) citric acid
Ans: (c)
104. Blue Vitriol is : [UPPCS 1990]
         (a) Copper sulphate
         (b) Calcium sulphate
         (c) Iron sulphate
         (d) Sodium sulphate
Ans: (a)
105. A bee-sting leaves an acid which causes pain and irritation. The injected acid is- [NDA, 2011]
         (a) Acetic acid
         (b) Sulphuric acid
         (c) Citric acid
         (d) Methanoic acid
Ans: (a)
106. The strong smell of a substance which is used in the colouration or painting is :
         (a) CaOH
         (b) AI2(SO4)3
         (c) CaCO3
         (d) Zn3(PO4)2
Ans: (d)
107. Which one of the following metal is the best conductor of electricity?
         (a) Gold
         (b) Silver
         (c) Copper
         (d) Zinc
Ans: (b)
108. The substance which is frequently used in the photography is : [UPPCS (Pre) 1992]
         (a) Silver Nitrate
         (b) Silver bromide
         (c) Sulphuric acid
         (d) Citric acid
Ans: (b)
109. Which one of the following metal is the heaviest? [CDS 1999]
         (a) Silver