JEE MainChemistryGeneral Organic Chemistry
In the Dumas method for the quantitative estimation of nitrogen, the gaseous mixture evolved from the combustion tube is passed over a heated copper gauze. The primary function of this copper gauze is:
Options
- Ato reduce traces of nitrogen oxides to nitrogen gas.
- Bto oxidize the carbon and hydrogen present in the organic compound.
- Cto absorb the carbon dioxide gas produced during combustion.
- Dto absorb the water vapour produced during combustion.
Correct answer
A. to reduce traces of nitrogen oxides to nitrogen gas.
Step-by-step solution
In the Dumas method, the organic compound is heated with copper oxide, which oxidizes carbon to CO₂ , hydrogen to H₂O , and nitrogen to free N₂ along with traces of nitrogen oxides ( NO_x ). The gaseous mixture is then passed over a heated copper gauze. The copper gauze acts as a reducing agent, converting any traces of nitrogen oxides back into pure nitrogen gas ( N₂ ). The other options describe the roles of copper oxide (oxidizing agent), aqueous potassium hydroxide (absorbs CO₂ ), and desiccants (absorb water),