Study of Estimation of Hardness of Water Using pH-Meter

The hardness of water is one of the important parameters of water quality. The complexometric titration method is a prevalent technique to estimate concentrations of and ions individually, which are primarily responsible for the hardness of water. However, the method needs two external indicators to mark the end points of titrations. Furthermore, accuracy of the method is sacrificed due to inevitable parallax errors during marking of the endpoint of titration. This present work reports that during titration of a hard water sample with a complexing agent (here, solution), changes continuously. This change in is closely monitored and recorded graphically. Hence the endpoint of titration is determined. The neutralization volume, thus obtained, is used to estimate and hardness of the water sample separately. This novel technique obviates the use of any external indicators and eliminates any possible parallax error.