JEE Main 2021 · ChemistryMultiple choiceSingle correctEasyRecall

JEE Main 4 August 2021, Shift 2, Chemistry Q50

Question 50 of 90 in this shift, Chemistry question 20 of 30, Section A.

The reagent that gives purple coloured complex with

\mathrm{S^{2-}}

ion is

(1) $\mathrm{Na_4\ [Fe(CN)_5\ NOS]}$
(2) $\mathrm{Na_2\ [Fe(CN)_5\ NO]}$ Official answer
(3) $\mathrm{Na_2\ [Fe(CN)_5\ ONO]}$
(4) $\mathrm{Na_4\ [Fe(CN)_5\ ONO]}$

Official answer

Option 2

NTA final key.

Chapter: Coordination Compounds
Topic: Anion Analysis
Idea tested: Sulfide Sodium Nitroprusside Test

Same idea in other shifts

Asked 4× in all

2 Apr 2025, Shift 2 · Q62Formation of $\mathrm{Na_4[Fe(CN)_5NOS]}$ , a purple coloured complex formed by addition of sodium nitroprusside in sodium carbonate…EasySingle correct
28 Jun 2022, Shift 1 · Q80The formula of the purple colour formed in Laissaigne’s test for sulphur using sodium nitroprusside isEasySingle correct
26 Aug 2021, Shift 1 · Q41Which one of the following complexes is violet in colour ?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.