Given below are two statements : One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Clothes containing oil or grease stains cannot be cleaned by water wash. Reason (R) : Because the angle of contact between the oil/ grease and water is obtuse. In the light of the above statements, choose the correct answer from the option given below.
(A)Both (A) and (R) are true and (R) is the correct explanation of (A)✓ Correct
(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 true but (R) is true
Answer: (A)
Solution
When the angle of contact between water and oil/grease is obtuse (greater than 90°), water does not wet the oily surface. This means water cannot penetrate and remove the oil/grease stains effectively. Both statements are true, and the obtuse angle of contact (Reason R) correctly explains why water cannot clean oil/grease stains (Assertion A).
JEE Main · 2022 · 29 Jul 2022 · Shift 1 · Single correct option
