171. Which of the following are not concentrated by froth floatation method ?

1. 1. Copper pyrite

   
   
   

   2. Pentlandite

   
   
   

   3. Pyrolusite

   
   
   

   4. Zinc blende

   
   
   

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   NA

   Correct Option: B

   NA

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172. An example of halide ores is

1. 1. Bauxite

   
   
   

   2. Cinnabar

   
   
   

   3. Cryolite

   
   
   

   4. Galena

   
   
   

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   NA

   Correct Option: C

   NA

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173. Alkali metals in each period have

1. 1. Lowest IE

   
   
   

   2. Highest IE

   
   
   

   3. High electro-negativity

   
   
   

   4. None of these

   
   
   

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   NA

   Correct Option: A

   NA

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174. Steel differs from pig iron and wrought iron that it contains

1. 1. Less carbon

   
   
   

   2. More carbon

   
   
   

   3. Amount of carbon intermediate between these tow

   
   
   

   4. No carbon at all

   
   
   

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   NA

   Correct Option: C

   NA

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175. When sodium bicarbonate is heated the product obtained is

1. 1. Na

   
   
   

   2. NaCO₃

   
   
   

   3. NaHCO₃

   
   
   

   4. Na₂OC₃

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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