Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : An aqueous solution of KOH when for volumetric analysis, its concentration should be checked before the use.
Reason (R) : On aging, KOH solution absorbs atmospheric .
In the light of the above statements, choose the correct answer from the options given below.
Assertion (A) : An aqueous solution of KOH when for volumetric analysis, its concentration should be checked before the use.
Reason (R) : On aging, KOH solution absorbs atmospheric .
In the light of the above statements, choose the correct answer from the options given below.
- (A)(A) is not correct but (R) is correct
- (B)Both (A) and (R) are correct but (R) is not the correct explanation of (A)
- (C)Both (A) and (R) are correct and (R) is the correct explanation of (A)✓ Correct
- (D)(A) is correct but (R) is not correct
Answer: (C)
Solution
A standard solution of potassium hydroxide used in titrations must have its strength verified before use because its concentration does not remain constant on standing. The cause is that potassium hydroxide absorbs carbon dioxide from the air, , converting part of the alkali to carbonate and lowering the available hydroxide. This absorption is exactly why the concentration drifts and must be re-measured, so both statements are correct and the reason correctly explains the assertion.
JEE Main · 2023 · 01 Feb 2023 · Shift 2 · Single correct option