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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceSingle correctEasyRecall

JEE Main 4 August 2021, Shift 2, Chemistry Q37

Question 37 of 90 in this shift, Chemistry question 7 of 30, Section A.

Ruby and emerald are coloured due to the presence of
  1. (1)Chromium(III) in both.Official answer
  2. (2)Chromium(III) and Chromium(II) respectively.
  3. (3)Chromium(III) and Copper(II) respectively.
  4. (4)Chromium(II) and Copper(II) respectively.

Official answer

Option 1

NTA final key.

Chapter
The d- and f-Block Elements
Topic
d-Block Elements
Idea tested
Color and Catalysis

Same idea in other shifts

Asked 7× in all
  1. 8 Apr 2026, Shift 2 · Q60Given below are two statements : Statement I : The number of pairs among [Ti4+,V2+][\mathrm{Ti^{4+}, V^{2+}}], [V2+,Mn2+][\mathrm{V^{2+}, Mn^{2+}}],…MediumTwo statements
  2. 1 Feb 2024, Shift 2 · Q71Which of the following compounds show colour due to d-d transition ?EasySingle correct
  3. 29 Jul 2022, Shift 1 · Q69In following pairs, the one in which both transition metal ions are colourless is :EasySingle correct
  4. 30 Jul 2022, Shift 2 · Q58The number of coloured and paramagnetic ions from the following in aqueous solution are ________. Ti3+\mathrm{Ti^{3+}}, Co2+\mathrm{Co^{2+}},…MediumNumerical value
  5. 3 Aug 2021, Shift 2 · Q38Which one of the following set will give coloured aqueous solution?EasySingle correct
  6. 26 Aug 2021, Shift 1 · Q39Which one of the following when dissolved in water gives coloured solution in nitrogen atmosphere ?EasySingle 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.