236. Consider the following statements
     1. Baking soda is used in fire extinguishers
     2. Quick lime is used in the manufacture of glass
     3. Gypsom is used in manufacture of plaster of paris
     Which of the statements given above is/are correct ?

1. 1. 1 and 2

   
   
   

   2. 2 and 3

   
   
   

   3. 1 only

   
   
   

   4. 1, 2 and 3

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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237. When metal is obtained in the molten state from its ore, the process may be called

1. 1. Rusting

   
   
   

   2. Smelting

   
   
   

   3. Calcination

   
   
   

   4. Thermal dissociation

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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238. The formula of haematite is

1. 1. Fe₃O₄

   
   
   

   2. Fe₂O₃

   
   
   

   3. FeCO₃

   
   
   

   4. FeS₂

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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239. The solubility of AgBr in hypo is due to the formation of

1. 1. Ag₂S₂O₃

   
   
   

   2. [Ag(S₂O₃)]^-

   
   
   

   3. [Ag(S₂O₃)]^3-

   
   
   

   4. Ag₂SO₃

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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240. The percentage of gold in 21.6 carat of gold is

1. 1. 80%

   
   
   

   2. 90%

   
   
   

   3. 21.6%

   
   
   

   4. 43.2%

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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