281. Quartz is a crustalline variety of

1. 1. Silicon

   
   
   

   2. Silicon carbide

   
   
   

   3. Sodium silicate

   
   
   

   4. Silica

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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282. Ultra silicon is prepared by the process of

1. 1. Crystallization

   
   
   

   2. Sublimation

   
   
   

   3. Zone refining

   
   
   

   4. Fractional distillation

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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283. Biogas and producer gas are made of

1. 1. Producer gas contains CO but not CO₂

   
   
   

   2. Biogas contains CO₂ but producer gas does not

   
   
   

   3. Both biogas and producer gas have N₂

   
   
   

   4. All of them

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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284. The electronic configuration of Si is

1. 1. [Ne] 3s²3p²

   
   
   

   2. [Kr] 4d¹⁰5s²5p²

   
   
   

   3. [He] 2s²2p²

   
   
   

   4. [Ar] 3d¹⁰ 4s²4p²

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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285. Red phosphorus is less reactive than yellow phosphorus because

1. 1. It is highly colour

   
   
   

   2. It is highly polymerised

   
   
   

   3. It is insoluble in C₂H₅OH

   
   
   

   4. It is hard

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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