JEE Main 2021 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 25 July 2021, Shift 1, Chemistry Q51

Question 51 of 90 in this shift, Chemistry question 21 of 30, Section B.

When 10 mL of an aqueous solution of

\mathrm{Fe^{2+}}

ions was titrated in the presence of dil

\mathrm{H_2SO_4}

using diphenylamine indicator, 15 mL of 0.02 M solution of

\mathrm{K_2Cr_2O_7}

was required to get the end point. The molarity of the solution containing

\mathrm{Fe^{2+}}

ions is

x\times10^{-2}

M. The value of

x

is _________. (Nearest integer)

Official answer

NTA final key.

Chapter: Some Basic Concepts of Chemistry
Topic: Redox Reactions
Idea tested: Mohr's Salt Redox Titrations

Same topic in other shifts

All Redox Reactions questions

2 Apr 2026, Shift 1 · Q61Which of the following sets includes all the species that will change the orange colour of $\mathrm{K_2Cr_2O_7}$ in acidic medium ?MediumSingle correct
4 Apr 2026, Shift 1 · Q56In order to oxidise a mixture of $1$ mole each of $\mathrm{FeC_2O_4}$ , $\mathrm{Fe_2(C_2O_4)_3}$ , $\mathrm{FeSO_4}$ and…MediumSingle correct
6 Apr 2026, Shift 2 · Q73500 mL of 0.2 M $\mathrm{MnO_4^-}$ solution in basic medium when mixed with 500 mL of 1.5 M KI solution, oxidises iodide ions to liberate…MediumNumerical value
6 Apr 2024, Shift 2 · Q64Match List - I with List - II. List - I (Reaction) (A) $\mathrm{N_{2(g)}+O_{2(g)}\rightarrow 2NO_{(g)}}$ (B)…EasyMatch the list
8 Apr 2024, Shift 1 · Q64Thiosulphate reacts differently with iodine and bromine in the reactions given below:…MediumSingle correct
9 Apr 2024, Shift 1 · Q65Given below are two statements : Statement (I) : The oxidation state of an element in a particular compound is the charge acquired by its…MediumTwo statements

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.