CaCO$_{3}$ equivalents, volumetric analysis, hardness of water, titration, cations, freshman engineering students and their teachers.
Abstract
There are many books and websites which explain why thehardness of water is expressed as equivalent of CaCO3, butthey are not lucid enough to be comprehensible for first-yearengineering students. An earnest attempt is made in the followingdidactic short communication to comprehend the rationalebehind expressing the hardness of water as CaCO$_{3}$equivalent. Further, freshmen students in their volumetricanalysis calculations are unsure why the number of moles n$_{A}$and n$_{B}$ appear in the basic volumetric relation M$_{A}$V$_{A}$/n$_{A}$ =M$_{B}$V$_{B}$/n$_{B}$, and the same do not appear in another basic volumetricrelation N$_{A}$V$_{A}$ = N$_{B}$V$_{B}$. This article endeavors topresent a lucid account of this aspect—it does not convey anynew concept but ameliorates classroom teaching.
