Q2(b)(i). Acid-catalysed hydration of 3,3-dimethylbut-1-ene
The following reaction (3,3-dimethylbut-1-ene with cat. H₂SO₄, H₂O) does not produce the product shown. 1. Predict the major product from the conditions shown, and write a detailed mechanism for its formation. 2. Write the reaction conditions which would lead to successful synthesis of the product shown (i.e., 3,3-dimethyl-2-butanol). [reaction given in the paper]
Model answer
The free solution for 2025 answers questions 1, 3, 5, 6 and 8, the ones picked in its time plan. Question 2 is answered in full in the Chemistry Paper II, 2021 to 2025 book, with every part of every paper.
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UPSC Civil Services (Main) Chemistry Paper II: Model Answers 2021 to 2025
- All eight questions of each paper, with the question printed above its answer
- Mechanisms drawn out and labelled on the scheme
- Topic-wise weightage and a topic-wise index
Coversacid-catalysed hydrationcarbocation rearrangement1,2-methyl shiftoxymercuration–demercuration3,3-dimethylbut-1-ene
All parts of Question 2
- 2(a) Ester shift with sodium ethoxide; cyclisation of an epoxy-diene15 marks
- 2(b)(i) Acid-catalysed hydration of 3,3-dimethylbut-1-ene10 marks
- 2(b)(ii) Styrene with BrCCl₃ under light5 marks
- 2(c) Products of four reactions20 marks