UPSC Combined Geo-Scientist, Mains · 2023 · Mains Paper II
Q9(b). Primary salt effect for persulfate and iodide
Question
Justify or criticize the following statement: For the ionic reaction S₂O₈²⁻ + I⁻ → I₂ + 2SO₄²⁻, the reaction rate constant decreases with increase in ionic strength.
Model answer
The free solution for 2023 answers questions 1, 2, 3, 4, 6, 8, 10, 11, 13 and 14, the ones picked in its time plan. Question 9 is answered in full in the Geo-Scientist Chemistry Paper II, 2021 to 2025 book, with every part of every paper.
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UPSC Combined Geo-Scientist (Main) Chemistry Paper II: Model Answers 2021 to 2025
- All fifteen questions of each paper, with the question printed above its answer
- Numericals worked from formula to result with units; graphs with labelled axes
- Topic-wise weightage and a topic-wise index
Coversprimary salt effectBrønsted–Bjerrum equationionic strengthpersulfate–iodide reactionkinetic salt effect
All parts of Question 9
- 9(a) Half-life method for the order of reaction2 marks
- 9(b) Primary salt effect for persulfate and iodide2 marks
- 9(c) Entropy change on adsorption2 marks
- 9(d) Resonance fluorescence of atoms2 marks
- 9(e) Phosphorescence delayed, fluorescence prompt2 marks