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Friday, 9 October

JEE Main 2025 · ChemistryMultiple choiceOtherMediumRecall

JEE Main 2 April 2025, Shift 1, Chemistry Q62

Question 62 of 75 in this shift, Chemistry question 12 of 25, Section A.

Choose the correct tests with respective observations. (A) CuSO4\mathrm{CuSO_4} (acidified with acetic acid) + K4[Fe(CN)6]→\mathrm{K_4[Fe(CN)_6]}\rightarrow Chocolate brown precipitate. (B) FeCl3\mathrm{FeCl_3} + K4[Fe(CN)6]→\mathrm{K_4[Fe(CN)_6]}\rightarrow Prussian blue precipitate. (C) ZnCl2\mathrm{ZnCl_2} + K4[Fe(CN)6]\mathrm{K_4[Fe(CN)_6]}, neutralised with NH4OH→\mathrm{NH_4OH}\rightarrow White or bluish white precipitate. (D) MgCl2\mathrm{MgCl_2} + K4[Fe(CN)6]→\mathrm{K_4[Fe(CN)_6]}\rightarrow Blue precipitate. (E) BaCl2\mathrm{BaCl_2} + K4[Fe(CN)6]\mathrm{K_4[Fe(CN)_6]}, neutralised with NaOH →\rightarrow White precipitate. Choose the correct answer from the options given below :
  1. (1)A, B and C onlyOfficial answer
  2. (2)B, D and E only
  3. (3)C, D and E only
  4. (4)A, D and E only

Official answer

Option 1

NTA final key.

Chapter
The d- and f-Block Elements
Topic
Cation Analysis
Idea tested
Group II: Copper Ferrocyanide Test

Same topic in other shifts

All Cation Analysis questions
  1. 2 Apr 2026, Shift 1 · Q70A salt with few drops of conc. HCl gives apple green colour in flame test. The group precipitate of the salt is dissolved in acetic acid…MediumSingle correct
  2. 4 Apr 2026, Shift 2 · Q69Among Fe3+\mathrm{Fe^{3+}}, Pb2+\mathrm{Pb^{2+}}, Cu2+\mathrm{Cu^{2+}} and Mn2+\mathrm{Mn^{2+}}, identify the one that gets precipitated out while…MediumSingle correct
  3. 7 Apr 2025, Shift 1 · Q63When a salt is treated with sodium hydroxide solution it gives gas X. On passing gas X through reagent Y a brown coloured precipitate is…EasySingle correct
  4. 6 Apr 2024, Shift 2 · Q87Consider the following reactions NiS+HNO3+HCl→A+NO+S+H2O\mathrm{NiS + HNO_3 + HCl \rightarrow A + NO + S + H_2O}…HardNumerical value
  5. 8 Apr 2024, Shift 1 · Q72Match List I with List II LIST I (Name of the test): A. Borax bead test; B. Charcoal cavity test; C. Cobalt nitrate test; D. Flame test…MediumMatch the list
  6. 9 Apr 2024, Shift 2 · Q87Consider the following test for a group-IV cation. M2++H2S→A\mathrm{M^{2+} + H_2S \rightarrow A} (Black precipitate) + byproduct A\mathrm{A} +…HardNumerical 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 42 of the 174 JEE Main shifts held from 2017 to 2026.