VKC Blog
PYQs explained, strategy, answer writing and video notes for UPSC Chemistry
Every post for Civil Services, Geo-Scientist and IFoS chemistry, in one place. 11 posts so far; new ones are announced on Telegram first.
Videos
Strategy and booklist videos from the VKC YouTube channel, written up so you can come back to them.
UPSC Chemistry optional booklist: one unit, one book
Made from the 17 chemistry books I have read: the one best book for every unit of Paper I and Paper II, which four books carry over half the marks, and two plans, for 2027 and for college students. With the 36-minute video.
Geo-Scientist Prelims Chemistry (Paper II) strategy: 720 PYQs, 12 units, one plan
Why Paper II decides Stage I, what 720 Chemistry PYQs say unit by unit, the 29 sure-shot topic families, one book per block and a 10-week plan. With the 32-minute video.
Geo-Scientist Prelims GS strategy for every stream: what 720 PYQs say
All 720 GS questions of 2021 to 2026 sorted by subject, a 50+ marks plan for geologists, geophysicists and chemists, one source per subject and an 11-week plan. With the 30-minute video.
PYQ explained
One commonly asked question at a time: where it comes from, the keyword map and a model answer. Each has its Daily Answer Writing video.
MO diagram of NO: why NO⁺ has a shorter bond and a higher stretching frequency
Take one electron away and the bond gets stronger. MO theory of diatomics came 9 times for 100 marks from 2021 to 2025: book source, keyword map and a model answer. Day 05 video.
Neopentyl bromide: why SN2 is very slow and solvolysis gives rearranged products
A primary bromide that will not do SN2, and an SN1 that changes the skeleton. Asked in 11 of 15 papers from 2021 to 2025: book source, keyword map and a model answer. Day 03 video.
Crystal field theory: why [CoF₆]³⁻ is paramagnetic but [Co(CN)₆]³⁻ is diamagnetic
Asked in 14 of 15 papers from 2021 to 2025 across CSE, Geo-Scientist and IFoS: book source, keyword map and a two-page model answer.
Woodward–Fieser rules: calculating λmax of enones and dienes
Asked in CSE, Geo-Scientist and IFoS from 2022 to 2025: book source, keyword map and a two-page model answer.
Particle in a box: probability in part of the box
Asked in CSE 2025, CSE 2022 and Geo-Scientist 2021: book source, keyword map and a three-page model answer.
Strategy
How the paper is built and how to use your three hours.
Answer writing
How to lay out an answer so the examiner sees every step.