Question

In Dumas method for the estimation of nitrogen in an organic compound, nitrogen is determined in the form of:
A) Gaseous nitrogen.
B) Sodium Cyanide.
C) Ammonium sulphate.
D) Gaseous ammonia.

Answer 1

Hint:We must remember that the Dumas’ method is a method used for quantitative nitrogen content. The product of this method is a mixture of gases from which a diatomic gas is isolated which has atomic number seven and is present in abundant amounts in the earth’s atmosphere.

Complete step by step answer: Now we can discuss Duma's method and how it works.
Dumas' method:
In Dumas method, a known mass of the compound is heated with cupric oxide in an environment of $$C{O}_2$$. The carbon and hydrogen within the compound are oxidized to $$C{O}_2$$ and water respectively, while nitrogen is about free. The oxides of nitrogen produced are reduced to nitrogen by heated copper gauze. The gaseous mixture consisting of $$C{O}_2$$, $$H_{2}O$$ and $$N_2$$ is collected over a solution of potash. Except nitrogen all the gases are absorbed by the solution. The quantity of gas (nitrogen) collected is measured.

Therefore, the option A is correct.


Note: Now we discuss the advantages and limitations of Dumas method.
The Dumas method has the benefits of being easy to use and fully automatable. It has been developed into a considerably faster method than the Kjeldahl method, and may take a couple of minutes per measurement, as compared to the hour or more for Kjeldahl. It also doesn't make use of toxic chemicals or catalysts. Also, like Kjeldahl, it doesn't provide a measure of true protein, because it registers non-protein nitrogen, and different correction factors are needed for various proteins because they need different amino alkanoic acid sequences.