UPSC Combined Geo-Scientist, Mains · 2016 · Mains Paper III
Q4(c). Acid–base indicators: methyl orange and phenolphthalein
Question
Define acid-base indicator. Suggest the transition pH range with colour changes in methyl orange and phenolphthalein indicators.
Model answer
The free solution for 2016 answers questions 1, 2, 3, 5, 6, 7, 9, 10, 11 and 12, the ones picked in its time plan. This part is not answered on the site yet. New answers are announced on Telegram.
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Coversacid-base indicatormethyl orangephenolphthaleintransition range
All parts of Question 4
- 4(a) [H₃O⁺] of a phosphoric acid–hydrogen phosphate buffer5 marks
- 4(b) CO₂ and H₂O from combustion of 4.635 mg benzoic acid5 marks
- 4(c) Acid–base indicators: methyl orange and phenolphthalein5 marks