Question

Why do we need to standardize EDTA in determination of water hardness?​

Answer 1

a specific amount edta is added to a specific amount of distilled water

Step-by-step explanation:

Answer 2

Standardized means that a specific amount EDTA is added to a specific volume of distilled water. Water hardness is determined by the the amount of a standard EDTA solution to change the color of the water from red to blue. For example if one added the correct amount of EDTA to twice the volume of distilled water the solution would be weak. Titration of the hard water would give a erroneous high result.