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Saturday, 31 October

JEE Main · Chemistry · Hydrogen

Causes of Temporary and Permanent Hardness

JEE Main asked Causes of Temporary and Permanent Hardness 2 times in 2 of the 108 shifts Lumi analysed, in 2020 and 2022. It belongs to Hydrogen and Hydrides, in Hydrogen (Chemistry). The longest wait between two years asking it was 2 years.

Updated 2026-10-24

Times asked
2
in 2 shifts
Years
2 of 8
First asked
2020
last in 2022
Pattern
Occasional
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2020 and 2022. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.050.10’170.08’200’210.03’220’230’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 1 in 12 shifts · 2021: 0 in 24 shifts · 2022: 1 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20240 of 18
  • 20230 of 12
  • 20221 of 24
  • 20210 of 24
  • 20201 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Numerical value is the usual form. Skill tested: calculation.

  • Statement selection on water hardness
  • Hardness as caco3 equivalent ppm

Difficulty

Easy 0Medium 2Hard 0

1 of the 2 questions had a numerical answer.

Every question

All 2 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 30 Jul 2022, Shift 2 · Q37The hardness of water is generally expressed in terms of CaCO3\mathrm{CaCO_3} equivalent. The possible reasons are as follows: (A) Its molar…MediumOther
  2. 9 Jan 2020, Shift 1 · Q49The hardness of a water sample containing 10−310^{-3} M MgSO4\mathrm{MgSO_4} expressed as CaCO3\mathrm{CaCO_3} equivalents (in ppm) is ________.…MediumNumerical value

Shifts: 9 Jan 2020, Shift 1, 30 Jul 2022, Shift 2.

Same topic

Other ideas in Hydrogen and Hydrides

Hydrogen and Hydrides has 29 ideas JEE Main has asked; 21 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisAll repeated ideas