Solution

Potassium dichromate: It is commonly used as an oxidizing agent in the determination of soil organic matter content. It reacts with organic matter, and the change in color indicates the amount of organic matter present. Ferrous ammonium sulphate: This reagent is used as a reducing agent in the soil organic matter determination. It reacts with the excess potassium dichromate after the oxidation reaction is complete. Diphenyl amine: It is used as an indicator in the determination of soil organic matter. It reacts with the reduced form of chromium, resulting in a color change. Sulphuric acid: Sulphuric acid is commonly used as a digestion reagent in the determination of soil organic matter. It helps break down organic matter and facilitates the oxidation process.