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 used for volumetric analysis, its concentratio

Question

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 used 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.

Canvas Classes · Accepted Answer

Step 1 — Evaluate Assertion (A):

KOH solution is used as a standard base in volumetric analysis. However, KOH is not a primary standard because:
- It absorbs  from air: 
- This changes the effective concentration of KOH over time

Therefore, its concentration must be checked (standardised) before use.
Assertion (A) is CORRECT ✓

Step 2 — Evaluate Reason (R):

KOH solution does indeed absorb atmospheric  on aging, converting KOH to . This reduces the KOH concentration and introduces , which has

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