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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceSingle correctMediumMulti-step

JEE Main 30 January 2024, Shift 2, Chemistry Q80

Question 80 of 90 in this shift, Chemistry question 20 of 30, Section A.

A and B formed in the following reactions are: CrO2Cl2+4NaOH→A+2NaCl+2H2O\mathrm{CrO_2Cl_2} + 4\mathrm{NaOH} \to A + 2\mathrm{NaCl} + 2\mathrm{H_2O} A+2HCl+2H2O2→B+3H2OA + 2\mathrm{HCl} + 2\mathrm{H_2O_2} \to B + 3\mathrm{H_2O}
  1. (1)A=Na2Cr2O7, B=CrO3A = \mathrm{Na_2Cr_2O_7},\ B = \mathrm{CrO_3}
  2. (2)A=Na2Cr2O4, B=CrO4A = \mathrm{Na_2Cr_2O_4},\ B = \mathrm{CrO_4}
  3. (3)A=Na2Cr2O7, B=CrO5A = \mathrm{Na_2Cr_2O_7},\ B = \mathrm{CrO_5}
  4. (4)A=Na2CrO4, B=CrO5A = \mathrm{Na_2CrO_4},\ B = \mathrm{CrO_5}Official answer

Official answer

Option 4

NTA final key.

Chapter
The d- and f-Block Elements
Topic
d-Block Elements
Idea tested
Chromyl Chloride Test Reactions

Same idea in other shifts

Asked 3× in all
  1. 27 Jan 2024, Shift 1 · Q80NaCl reacts with conc. H2SO4\mathrm{H_2SO_4} and K2Cr2O7\mathrm{K_2Cr_2O_7} to give reddish fumes (B), which react with NaOH to give yellow…MediumSingle correct
  2. 31 Jan 2024, Shift 2 · Q90In the reaction of potassium dichromate, potassium chloride and sulfuric acid (conc.), the oxidation state of the chromium in the product…EasyNumerical 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.