JEE Main 2019 — Redox Reactions Question with Solution
From: JEE Main 2019 (Online) 12th January Morning Slot
Question
The hardness of a water sample (in terms of equivalents of CaCO3) containing 10–3 M CaSO4 is (Molar mass of CaSO4 = 136 g mol–1)
Choose an option
Show full solutionCorrect option: B
Correct answer
B100 ppm
Step-by-step explanation
nCaSO4 Van't hoff factor = nCaCO3 Van't hoff factor
10-3 2 = nCaCO3 2
nCaCO3 = 10-3 mol in 1 L
wCaCO3 = 100 10-3 g CaCO3 in 1 L solution
hardness in terms of CaCO3
=
=
= 100 ppm
10-3 2 = nCaCO3 2
nCaCO3 = 10-3 mol in 1 L
wCaCO3 = 100 10-3 g CaCO3 in 1 L solution
hardness in terms of CaCO3
=
=
= 100 ppm
Practice this on the real CBT interface
Solve this JEE Main question (and the rest of the Redox Reactions chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.
Solve interactively →About this question
This is a previous-year question from JEE Main 2019, covering the Redox Reactions chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.