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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctMediumCalculation

JEE Main 3 September 2020, Shift 2, Chemistry Q36

Question 36 of 75 in this shift, Chemistry question 11 of 25.

Complex A has a composition of H12O6Cl3Cr\mathrm{H_{12}O_6Cl_3Cr}. If the complex on treatment with conc. H2SO4\mathrm{H_2SO_4} loses 13.5% of its original mass, the correct molecular formula of A is : [Given : atomic mass of Cr=52 amu and Cl=35 amu]
  1. (1)[Cr(H2O)5Cl]Cl2⋅H2O\mathrm{[Cr(H_2O)_5Cl]Cl_2 \cdot H_2O}
  2. (2)[Cr(H2O)4Cl2]Cl⋅2H2O\mathrm{[Cr(H_2O)_4Cl_2]Cl \cdot 2H_2O}Official answer
  3. (3)[Cr(H2O)3Cl3]⋅3H2O\mathrm{[Cr(H_2O)_3Cl_3] \cdot 3H_2O}
  4. (4)[Cr(H2O)6]Cl3\mathrm{[Cr(H_2O)_6]Cl_3}

Official answer

Option 2

NTA final key (Sep 2020).

Chapter
Coordination Compounds
Topic
Coordination Isomerism
Idea tested
Dehydration of Hydrate Isomers

Same topic in other shifts

All Coordination Isomerism questions
  1. 2 Apr 2026, Shift 1 · Q715.335.33 g of CrCl3⋅6H2O\mathrm{CrCl_3{\cdot}6H_2O}, which is a 1:31:3 electrolyte, is dissolved in water and is passed through a cation exchanger.…HardNumerical value
  2. 2 Apr 2026, Shift 2 · Q61Which of the following complexes will show coordination isomerism? A. [Ag(NH3)2][Ag(CN)2][Ag(NH_3)_2][Ag(CN)_2] B. [Co(NH3)6][Cr(CN)6][Co(NH_3)_6][Cr(CN)_6] C.…MediumSingle correct
  3. 5 Apr 2026, Shift 2 · Q61Identify the correct statements from the following A. [Fe(C2O4)3]3−\mathrm{[Fe(C_2O_4)_3]^{3-}} is the most stable complex among…HardOther
  4. 6 Apr 2026, Shift 2 · Q71An excess of AgNO3\mathrm{AgNO_3} is added to 100 mL of a 0.05 M solution of tetraaquadichloridochromium (III) chloride. The number of moles…EasyNumerical value
  5. 3 Apr 2025, Shift 1 · Q72The number of optical isomers exhibited by the iron complex (A) obtained from the following reaction is ______.…MediumNumerical value
  6. 4 Apr 2025, Shift 2 · Q75A metal complex with a formula MCl4⋅3NH3\mathrm{MCl_4\cdot3NH_3} is involved in sp3d2\mathrm{sp^3d^2} hybridisation. It upon reaction with excess of…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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.