(b) ethane
         (c) ethylene
         (d) acetylene
Ans: (d)
190. The gas used in the weldings of the metallic joints is :
         (a) ethylene
         (b) acetylene
         (c) propylene
         (d) methane
Ans: (b)
191. Which one among the following is a source of methane emission into the atmosphere?
         (a) Automobile exhaust fume
         (b) Industrial chimney
         (c) Mining
         (d) Wetland
Ans: (d)
192. The toxic gas lewisite used in the war is prepared by :
         (a) chlorine
         (b) ammonia
         (c) acetylene
         (d) nitrobenzene
Ans: (c)
193. The element which has maximum number of isotopes is :
         (a) Bismuth
         (b) Nickel
         (c) Lead
         (d) Polonium
Ans: (d)
194. Which of the following chemically predominants in the silk fibres? [CDS 2010]
         (a) Protein
         (b) Carbohydrate
         (c) Complex lipid
         (d) Mixture of polysaccharide and fat
Ans: (b)
195. The chloroform is kept in the coloured bottle (container) because it directly reacts with air and light and forms a
         toxic substance which is:
         (a) phosphin
         (b) phosgene
         (c) mustard gas
         (d) CO
Ans: (b)
196. The carbon tetrachloride is also known as :
         (a) marsh gas
         (b) mustard gas
         (c) pyrin
         (d) pyrole
Ans: (c)
197. The fire extinguisher used in the electric firing is:
         (a) pyrin extinguisher
         (b) foam (leather) extinguisher
         (c) water extinguisher
         (d) soda acid extinguisher
Ans: (a)
198. Which of the following is also known as wood spirit:
         (a) methyl alcohol
         (b) ethyl alcohol
         (c) ethylene glycol
         (d) glycerol
Ans: (a)
199. The antifreezer is a mixture of :
         (a) acetic acid and water