261. Assertion (A) : Sodium metal is stored under kerosene.
     Reason (R) : Metallic sodium melts when exposed to air.
     Codes

1. 1. Both A and R is true and R is the correct explanation of A

   
   
   

   2. Both A and R is true but R is not a correct explanation of A

   
   
   

   3. A is true but R is false

   
   
   

   4. A is false but R is true

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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262. The electronic configuration of Cu²⁺ is

1. 1. [Ar]3d⁹

   
   
   

   2. [Ar]3d⁶ 4s² 4p¹

   
   
   

   3. [Ar]3d⁸ 4s¹

   
   
   

   4. [Ar]3d⁷ 4s²

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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263. Which of the following is most malleable ?

1. 1. Cu

   
   
   

   2. Ag

   
   
   

   3. Au

   
   
   

   4. none is malleable

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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264. Lithium reacts with nitrogen to form

1. 1. LiN

   
   
   

   2. Li₂N

   
   
   

   3. Li₃N

   
   
   

   4. Li₄N

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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265. Dead burnt is

1. 1. Anhydrous Na₂SO₄

   
   
   

   2. Na₂CO₃Which is useful for softening

   
   
   

   3. CaSO₄ Which is not useful for setting

   
   
   

   4. Anhydrous CuSO₄

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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