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Q:

Directions : For the Assertion (A) and Reason (R) below, choose the correct alternative 

Assertion(A)  : Graphite is slippery and used as a lubricant. 

Reason (R)    : Graphite has free electrons. 

A) Both A and R are true and R is the correct explanation of A. B) Both A and R are true but R is NOT the correct explanation of A.
C) A is true but R is false. D) A is false but R is true.

Answer:   B) Both A and R are true but R is NOT the correct explanation of A.



Explanation:

Graphite possesses a layer structure with two successive layers held by weak forces and able to slide over one another. So, graphite is slippery and this property finds its use as a lubricant. In graphite, each carbon atom is linked to three other carbon atoms while one electron in the carbon atom is delocalised. So, graphite has free electrons 

 

 

Q:

Directions : For the Assertion (A) and Reason (R) below, choose the correct alternative

Assertion (A) : An atom is neutral despite the charged particles in it. 

Reason (R) : The neutrons do not have any charge. 

A) Both A and R are true and R is the correct explanation of A. B) Both A and R are true but R is NOT the correct explanation of A.
C) A is true but R is false. D) A is false but R is true.
 
Answer & Explanation Answer: B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:

An atom contains the positively charged protons and an equal number of negatively charged electrons So, it is neutral

 

 

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Q:

Directions : For the Assertion (A) and Reason (R) below, choose the correct alternative 

Assertion (A) : Carbon monoxide when inhaled causes death. 

Reason (R) : Carbon monoxide combines with haemoglobin. 

A) Both A and R are true and R is the correct explanation of A. B) Both A and It are true but R is NOT the correct explanation of A.
C) A is true but R is false. D) A is false but R is true.
 
Answer & Explanation Answer: A) Both A and R are true and R is the correct explanation of A.

Explanation:

Carbon monoxide, when inhaled, combines with haemoglobin of blood to form carboxyhaemoglobin which inhibits the transport of oxygen. 

 

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