Question

Assertion (A): Aluminium has poor weldability.
Reason (R): Aluminium has high thermal conductivity and high affinity to oxygen.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Aluminium is weldable but requires controlled techniques due to oxide layer.

Answer 1

The Correct Option is D

Concept: Weldability depends on material properties like thermal conductivity and oxidation behavior.

Step 1: Evaluate Assertion (A).
Aluminium does NOT have poor weldability:
• It is widely weldable using TIG, MIG
• Special precautions required Thus Assertion is incorrect.

Step 2: Evaluate Reason (R).
Aluminium has:
• High thermal conductivity → heat dissipates quickly
• High affinity to oxygen → forms oxide layer This makes welding difficult but not impossible. Thus Reason is correct.

Step 3: Final logic.
(A) incorrect, (R) correct. Final Answer: \[ \boxed{\text{(A) is not correct but (R) is correct}} \]