in kjeldahl method, at the distillation step, we have to use NaOH solution,. in this solution we have sodium thiosulphate. what is the purpose of adding sodium thiosulphate?
In this process Hydrogen sulphide is produced, liberation of Hydrogen sulphide must be avoided and to avoid this Sodium Thiosulphate is added. With attention to this point, the liberation of hydrogen sulfide from the acid digest is avoided.