81. Which one of the following removes temporary hardness of water ?

1. 1. Slaked lime

   
   
   

   2. Hydrolith

   
   
   

   3. Plaster of paris

   
   
   

   4. Cuprous

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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82. The formula of sodium zeolite which is used in permutit process for softening water is

1. 1. Na₂OAI₂O₃Si₂O xH₂O

   
   
   

   2. Na₂OAI₂O₃SiO₄ xH₂O

   
   
   

   3. K₂AI₂SiO₈ xH₂O

   
   
   

   4. Na₂AI₂Si₂O₄ xH₂O

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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83. Which of the following glasses is used in making wind screen of automobiles

1. 1. Pyrex

   
   
   

   2. Jena

   
   
   

   3. Crook's

   
   
   

   4. Safety

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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84. Stannous fluoride is formede by

1. 1. Sn + HF

   
   
   

   2. SnO₂ + HF

   
   
   

   3. Sn + F

   
   
   

   4. SnO + HF

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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85. Ozone turns starch iodine paper

1. 1. Green

   
   
   

   2. Blue

   
   
   

   3. Red

   
   
   

   4. Black

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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