At the End Point of Titration of Organic Carbon Estimation colour changes

Answer: Option D

At the end point of the titration of Organic Carbon estimation colour changes from blue to green. At this point, the addition of ferrous sulphate drop by drop until the colour changes sharply from blue - green to reddish - grey.
The determination of soil organic carbon is based on the Walkley - Black chromic acid wet oxidation method. The reaction is assisted by the heat generated when two volumes of sulphuric acid are mixed with one volume of the dichromate.