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.
