(b) copper
     (c) calcium
     (d) magnesium
Ans: (d)
178. Washing soda is the common name for: [BSF 1990]
     (a) Calcium carbonate
     (b) Calcium bicarbonate
     (c) Sodium carbonate
     (d) Sodium bicarbonate
Ans: (c)
179. Which of the following gases is not known as greenhouse gas? [Bank PO 1995]
     (a) Carbon dioxide
     (b) Methane
     (c) Nitrous oxide
     (d) Hydrogen
Ans: (c)
180. Chemical formula for water glass is : [NDA 1993]
     (a) Na2SiO3
     (b) Al2O3
     (c) NaAlO2
     (d) CaSiO3
Ans: (a)
181. The gas usually tilled in the electric bulb is:
     (a) hydrogen
     (b) oxygen
     (c) nitrogen
     (d) carbon dioxide
Ans: (c)
182. Which of the following alloys is used for making magnets?
     (a) Duralumin
     (b) Stainless steel
     (c) Alnico
     (d) Magnalium
Ans: (c)
183. Two or more forms of a chemical element having different physical properties but rising to identical chemical
     compounds are called :
     (a) Allotropes
     (b) Isotopes
     (c) Isomers
     (d) Isotones
Ans: (a)
184. Which of the lubricant?
     (a) Graphite
     (b) Silica
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