Ans: (a)
192. The type of glass used in making lenses and prisms is: [NDA 1991]
     (a) soft glass
     (b) pyrex glass
     (c) jena glass
     (d) flint glass
Ans: (d)
193. What makes a lemon sour?
     (a) Tartaric acid
     (b) Hydrochloric acid
     (c) Citric acid
     (d) Acetic acid
Ans: (c)
194. A substance which can act both as an acid and a base is known as: [NDA 1993]
     (a) amorphous
     (b) allotropic
     (c) amphoteric
     (d) None of these
Ans: (c)
195. The gas which had leaked out of Union Carbide factory in Bhopal was:
     (a) sulphur dioxide
     (b) methyl cyanide
     (c) carbon monoxide
     (d) methyl isocynate
Ans: (d)
196. Which of the following gases is used for refrigeration? [NDA 1991]
     (a) Chlorine
     (b) Sulphur dioxide
     (c) Phosphine
     (d) Ammonia
Ans: (d)
197. Match the following:
     A. Limestone            1. Fertilizer industry
     B. Sandstone            2. Electrical industry
     C. Rock phosphate       3. Cement industry
     D. Mica                 4. Building material
          A          B       C          D
     (a)  1          3       4          2
     (b)  3          4       1          2
     (c)  3          4       2          1
     (d)  4          3       1          2