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Saturday, 31 October

JEE Main · Chemistry · Coordination Compounds

Oxidation State Calculation

JEE Main asked Oxidation State Calculation 7 times in 7 of the 108 shifts Lumi analysed, in 2020, 2021, 2022 and 2024. It belongs to Coordination Nomenclature, in Coordination Compounds (Chemistry). The longest wait between two years asking it was 2 years. In 2021 and 2022 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
7
in 7 shifts
Years
4 of 8
First asked
2020
last in 2024
Pattern
Comes in cycles
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2020, 2021, 2022 and 2024. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.050.10’170.08’200.10’210.07’220’230.05’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 1 in 12 shifts · 2021: 3 in 24 shifts · 2022: 2 in 24 shifts · 2023: 0 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20241 of 18
  • 20230 of 12
  • 20222 of 24
  • 20213 of 24
  • 20201 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Single correct is the usual form. Skill tested: calculation.

  • Oxidation states in coordination compounds
  • Formula of complex from precipitation data

Difficulty

Easy 3Medium 4Hard 0

3 of the 7 questions had a numerical answer.

Every question

All 7 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 8 Apr 2024, Shift 1 · Q70An octahedral complex with the formula CoCl3⋅nNH3\mathrm{CoCl_3\cdot nNH_3} upon reaction with excess of AgNO3\mathrm{AgNO_3} solution gives 2 moles…MediumSingle correct
  2. 30 Jul 2022, Shift 2 · Q50In the ring test of NO3−\mathrm{NO_3^-} ion what is the oxidation number of iron in the complex (brown ring)…MediumSingle correct
  3. 29 Jul 2022, Shift 2 · Q86Sum of oxidation state (magnitude) and coordination number of cobalt in Na[Co(bpy)Cl4]\mathrm{Na[Co(bpy)Cl_4]} is ____. (Given: bpy = [figure:…EasyNumerical valueHas a figure
  4. 4 Aug 2021, Shift 2 · Q38The oxidation states of Mn in Mn2(CO)10\mathrm{Mn_2(CO)_{10}}, [Mn(CO)5Br]\left[\mathrm{Mn(CO)_5Br}\right] and K[Mn(CN)6]\mathrm{K}\left[\mathrm{Mn(CN)_6}\right]…EasySingle correct
  5. 4 Aug 2021, Shift 1 · Q57Among the following species, the number of species with oxidation state of Fe in +3 is ________. A.…MediumNumerical valueHas a figure
  6. 3 Aug 2021, Shift 2 · Q40The oxidation states of Fe in [Fe(NCS)(NH3)5]SO4\mathrm{[Fe(NCS)(NH_3)_5]SO_4}, Na3[Fe(S2O3)3]\mathrm{Na_3[Fe(S_2O_3)_3]} and [Fe(CO)5]\mathrm{[Fe(CO)_5]} respectively areEasySingle correct
  7. 2 Sep 2020, Shift 1 · Q49The oxidation states of iron atoms in compounds (A), (B) and (C), respectively, are xx, yy and zz. The sum of xx, yy and zz is…MediumNumerical value

Shifts: 2 Sep 2020, Shift 1, 3 Aug 2021, Shift 2, 4 Aug 2021, Shift 2, 4 Aug 2021, Shift 1, 29 Jul 2022, Shift 2, 30 Jul 2022, Shift 2, 8 Apr 2024, Shift 1.

Same topic

Other ideas in Coordination Nomenclature

Coordination Nomenclature has 4 ideas JEE Main has asked; 1 of them came up in more than one question.

Topic analysisChapter analysisStudy this chapterAll repeated ideas