Q4(a). Assigning Co(III) absorption intensities
An approximately 'octahedral' complex of Co(III) with ammine and chlorido ligands gives two bands with εmax between 60 and 80 dm³ mol⁻¹ cm⁻¹, one weak peak with εmax = 2 dm³ mol⁻¹ cm⁻¹ and a strong band at higher energy with εmax = 2 × 10⁴ dm³ mol⁻¹ cm⁻¹. What do you suggest for the origin of these transitions?
Model answer
The free solution for 2021 answers questions 1, 2, 5, 6, 9 and 11, the ones picked in its time plan. Question 4 is answered in full in the Geo-Scientist Chemistry Paper I, 2021 to 2025 book, with every part of every paper.
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UPSC Combined Geo-Scientist (Main) Chemistry Paper I: Model Answers 2021 to 2025
- All eleven questions of each paper, with the question printed above its answer
- Titration, gravimetric and nuclear numericals worked with units; structures drawn
- Topic-wise weightage and a topic-wise index
Coverselectronic spectraselection rulesspin-forbidden transitioncharge transfer bandCo(III) complexesmolar absorptivity
All parts of Question 4
- 4(a) Assigning Co(III) absorption intensities15 marks
- 4(b)(i) Square-planar spin alternatives10 marks
- 4(b)(ii) Relative lability of cyanide complexes5 marks