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Saturday, 31 October

JEE Main 2023 · ChemistryMultiple choiceAssertion–reasonMediumConceptual

JEE Main 6 April 2023, Shift 2, Chemistry Q70

Question 70 of 90 in this shift, Chemistry question 10 of 30, Section A.

Given below are two statements: one is labelled as "Assertion A" and the other is labelled as "Reason R" Assertion A: In the complex Ni(CO)4\mathrm{Ni(CO)_4} and Fe(CO)5\mathrm{Fe(CO)_5}, the metals have zero oxidation state. Reason R: Low oxidation states are found when a complex has ligands capable of π\pi-donor character in addition to the σ\sigma-bonding. In the light of the above statements, choose the most appropriate answer from the options given below
  1. (1)Both A and R are correct and R is the correct explanation of A
  2. (2)Both A and R are correct but R is NOT the correct explanation of A
  3. (3)A is correct but R is not correctOfficial answer
  4. (4)A is not correct but R is correct

Official answer

Option 3

NTA final key.

Chapter
Coordination Compounds
Topic
Redox Reactions
Idea tested
Oxidation States in Metal Carbonyls

Same topic in other shifts

All Redox Reactions questions
  1. 2 Apr 2026, Shift 1 · Q61Which of the following sets includes all the species that will change the orange colour of K2Cr2O7\mathrm{K_2Cr_2O_7} in acidic medium ?MediumSingle correct
  2. 4 Apr 2026, Shift 1 · Q56In order to oxidise a mixture of 11 mole each of FeC2O4\mathrm{FeC_2O_4}, Fe2(C2O4)3\mathrm{Fe_2(C_2O_4)_3}, FeSO4\mathrm{FeSO_4} and…MediumSingle correct
  3. 6 Apr 2026, Shift 2 · Q73500 mL of 0.2 M MnO4−\mathrm{MnO_4^-} solution in basic medium when mixed with 500 mL of 1.5 M KI solution, oxidises iodide ions to liberate…MediumNumerical value
  4. 4 Apr 2024, Shift 1 · Q87Only 2 mL of KMnO4\mathrm{KMnO_4} solution of unknown molarity is required to reach the end point of a titration of 20 mL of oxalic acid (2…MediumNumerical value
  5. 6 Apr 2024, Shift 2 · Q64Match List - I with List - II. List - I (Reaction) (A) N2(g)+O2(g)→2NO(g)\mathrm{N_{2(g)}+O_{2(g)}\rightarrow 2NO_{(g)}} (B)…EasyMatch the list
  6. 8 Apr 2024, Shift 1 · Q64Thiosulphate reacts differently with iodine and bromine in the reactions given below:…MediumSingle correct

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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.