Ans: (b)
198. Match the following:
     A. Nitrolime           1. Rocket fuel
     B. Sodium thiosulphate 2. Refrigerant
     C. Liquid ammonia      3. Photography
     D. Hydrazine           4. Fertilizer
          A         B       C          D
     (a)  3         4       1          2
     (b)  3         2       4          1
     (c)  4         1       2          3
     (d)  4         3       2          1
Ans: (d)
199. Match the following:
     A. Lead                1. Galvanisation
     B. Selenium            2. Photo cells
     C. Magnesium           3. Car battery
     D. Zinc                4. Firework
          A         B       C          D
     (a)  2         3       1          4
     (b)  2         4       3          1
     (c)  3         4       2          1
     (d)  3         2       4          1
Ans: (d)
200. Match the following:
     Copper alloys          Use
     A. Brass               1. Gears and bearings
     B. Bronze              2. Caps of cartidges
     C. Gun metal           3. Springs and suspension filaments in electrical instruments
     D. Phosphor bronze     4. Resistance wire
     E. German silver       5. Control valves
          A         B       C          D       E
     (a)  2         5       1          3       4
     (b)  2         3       4          1       5
     (c)  3         1       2          5       4
     (d)  3         5       2          1       4
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