Reagents required for determination of soil organic matter in laboratory.

A. Potassium dichromate

B. Ferrous ammonium sulphate

C. Saffranine

D. Diphenyl amine

E. Sulphuric acid

Choose the correct answer from the options given below:

Solution

Potassium dichromate: It is used as an oxidizing agent in the Walkley-Black method, which is commonly used to determine soil organic matter content. Ferrous ammonium sulphate: It acts as a reducing agent in the Walkley-Black method to react with the excess potassium dichromate. Diphenyl amine: It is used as an indicator in the Walkley-Black method to determine the endpoint of the reaction between the oxidizing and reducing agents. Sulphuric acid: It is used as a digestion reagent to facilitate the breakdown of organic matter in the soil sample.