Question 4 - Assertion Reasoning Questions (MCQ) - Chapter 1 Class 10 - Chemical Reactions and Equations

Assertion (A): Sodium metal is stored under  kerosene.  

Reason (R): Metallic sodium melts when exposed  to air.  

Directions: In the following questions, a statement  of assertion (A) is followed by a statement of  reason (R). Mark the correct choice as:   

(a) Both assertion (A) and reason (R) are true and  reason (R) is the correct explanation of assertion  (A).  

(b) Both assertion (A) and reason (R) are true but  reason (R) is not the correct explanation of  assertion (A).  

(c) Assertion (A) is true but reason (R) is false.  

(d) Assertion (A) is false but reason (R) is true.

Answer

Sodium is a very reactive metal.  It is kept in kerosene to prevent it from coming in contact with oxygen and moisture. 

If this happens, it will react with the moisture present in  air and form sodium hydroxide. This is a strong  exothermic reaction , and a lot of heat is generated.

Also, Metallic sodium does not melt when exposed to air.  

Thus,

• Assertion is true
• Reasoning is false , as metallic sodium does not melt when exposed to air

So, the correct answer is (c)