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Saturday, 31 October

JEE Main 2022 · ChemistryMultiple choiceOtherMediumConceptual

JEE Main 30 July 2022, Shift 2, Chemistry Q37

Question 37 of 90 in this shift, Chemistry question 7 of 30, Section A.

The hardness of water is generally expressed in terms of CaCO3\mathrm{CaCO_3} equivalent. The possible reasons are as follows: (A) Its molar mass is 100, so the calculations become easier. (B) It decomposes at a temperature, 1200 K. (C) It is insoluble in water. (D) It is moisture insensitive. Choose correct option from the following for the reasons.
  1. (1)(A) and (B) only
  2. (2)(A) and (D) only
  3. (3)(B) and (D) only
  4. (4)(A), (B), and (C) onlyOfficial answer

Official answer

Option 4

NTA final key.

Chapter
Hydrogen
Topic
Hydrogen and Hydrides
Idea tested
Causes of Temporary and Permanent Hardness

Same idea in other shifts

Asked 2× in all
  1. 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

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.