Indian Forest Service (Mains), Chemistry optional · 2023 · Paper II
Q2(a). Third- and fourth-order Cannizzaro kinetics
Question
Explain third-order kinetics at low base concentration and fourth-order kinetics at higher base concentration in the Cannizzaro reaction.
Answer in brief
At low base, rate ∝ [RCHO]²[OH⁻]; at high base, a dianionic donor adds a term proportional to [RCHO]²[OH⁻]².
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CoversCannizzaro reaction kineticsthird-order kineticsfourth-order kineticshydride transfertetrahedral dianion
All parts of Question 2
- 2(a) Third- and fourth-order Cannizzaro kinetics10 marks
- 2(b) Halohydrin cyclization and chair populations10 marks
- 2(c) Lewis-acid dehydration and rearrangement10 marks
- 2(d) Butanone phenylhydrazone and Fischer cyclization10 marks