What are the functions of potassium hydroxide solution, concentrated tetraoxosulphate (vi) acid and heated iron filing in the preparation of nitrogen from air?
In the preparation of nitrogen from air, potassium hydroxide solution, concentrated tetraoxosulphate (VI) acid, and heated iron filings are used for different purposes:
1. Potassium Hydroxide (KOH) Solution: KOH solution is used to remove carbon dioxide (CO2) from the air. When air passes through the solution, the CO2 reacts with KOH to form potassium carbonate and water. This removal of CO2 is important because it can interfere with the subsequent reactions in the process.
2. Concentrated Tetraoxosulphate (VI) Acid (H2SO4): Concentrated H2SO4 is used as a drying agent. It helps to remove moisture from the air, which is essential because nitrogen gas easily absorbs water vapor. By removing moisture, H2SO4 ensures that the collected nitrogen gas is dry.
3. Heated Iron Filings: The iron filings act as a catalyst in the preparation of nitrogen. Iron serves as a catalyst to speed up the reaction in which oxygen (O2) in the air reacts with nitrogen (N2) to form nitrogen dioxide (NO2). The reaction is exothermic, and the heat generated by the reaction helps to maintain the reaction temperature. The equation for this reaction is:
2N2 + O2 -> 2NO2
Once nitrogen dioxide is formed, it can be cooled and then treated with water to form nitric acid (HNO3), which can be further processed to obtain nitrogen.
So, to summarize:
- Potassium hydroxide solution is used to remove carbon dioxide (CO2) from the air.
- Concentrated tetraoxosulphate (VI) acid acts as a drying agent, removing moisture from the air.
- Heated iron filings catalyze the reaction between nitrogen (N2) and oxygen (O2) to form nitrogen dioxide (NO2), which is further processed to obtain nitrogen.