156. Boron halides behave as Lewis base, because of their

1. 1. Electron deficient nature

   
   
   

   2. Acidic nature

   
   
   

   3. Ionic nature

   
   
   

   4. Covalent nature

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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157. Which variety of glass is used for the manufacture of optical glasses

1. 1. Sodium glass

   
   
   

   2. Flint glass

   
   
   

   3. Ground glass

   
   
   

   4. quartz

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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158. The process of slow and homogeneous cooling of glass is called

1. 1. Etching of glass

   
   
   

   2. Annealing of glass

   
   
   

   3. Enamelling of glass

   
   
   

   4. Denitrification of glass

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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159. Aqua-regia is a mixture of

1. 1. 3HCI + HNO₃

   
   
   

   2. H₃PO₄ + H₂SO₄

   
   
   

   3. 3HNO₃ + HCI

   
   
   

   4. HCI + CH₃COOH

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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160. Nitrates of all metals are

1. 1. Unstable

   
   
   

   2. Coloured

   
   
   

   3. Insoluble in water

   
   
   

   4. Soluble in water

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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