In base vs. acid titration, at the end point methyl orange is present as
Ionic Equilibrium · Class 11 · JEE Main Previous Year Question
In base vs. acid titration, at the end point methyl orange is present as
- a✓
Quinonoid form
- b
Heterocyclic form
- c
Phenolic form
- d
Benzenoid form
Quinonoid form
Methyl orange is an acid-base indicator that changes colour based on pH.
Step 1 — Structure of methyl orange:
- In acidic medium (pH < 3.1): exists as quinonoid form (red/pink colour)
- In basic medium (pH > 4.4): exists as benzenoid form (yellow colour)
Step 2 — At end point of base vs. acid titration: In a base vs. acid titration (base in burette, acid in flask), the end point is reached when the solution becomes slightly acidic (pH ≈ 3.1-4.4 for methyl orange).
At the end point, the solution is acidic methyl orange is in the quinonoid form (red/orange).
Answer: Option (1) — Quinonoid form
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