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Saturday, 31 October

JEE Main 2022 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 29 July 2022, Shift 2, Chemistry Q86

Question 86 of 90 in this shift, Chemistry question 26 of 30, Section B.

Sum of oxidation state (magnitude) and coordination number of cobalt in Na[Co(bpy)Cl4]\mathrm{Na[Co(bpy)Cl_4]} is ____. (Given: bpy = [figure: 2,2'-bipyridine, two pyridine rings joined by a single bond, with the two N atoms on the same side])

The figure, in words

Structure of bpy (2,2′-bipyridine): two linked pyridine rings with N atoms labelled.

Official answer

9

NTA final key.

Chapter
Coordination Compounds
Topic
Coordination Nomenclature
Idea tested
Oxidation State Calculation

Same idea in other shifts

Asked 7× in all
  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. 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
  4. 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
  5. 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
  6. 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

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.