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Oxygen is produced on an industrial scale by the liquefaction and fractional distillation of air - Leaving Cert Chemistry - Question B - 2010
Question B
Oxygen is produced on an industrial scale by the liquefaction and fractional distillation of air. (i) What substances are removed in the purification of the air fee... show full transcript
Worked Solution & Example Answer:Oxygen is produced on an industrial scale by the liquefaction and fractional distillation of air - Leaving Cert Chemistry - Question B - 2010
Step 1
What substances are removed in the purification of the air feedstock before it is liquefied?
Answer
The substances removed in the purification of the air feedstock before liquefaction include dust, moisture, and carbon dioxide. These components are essential to eliminate as they can interfere with the liquefaction process and affect the purity of the final oxygen product.
Step 2
Describe with the aid of a labelled diagram how the fractional distillation of the pure liquid air is carried out.
Answer
The fractional distillation of pure liquid air begins with the compression of air, which is then allowed to cool. In the distillation column, liquid air warms up. The liquid oxygen, having the highest boiling point, collects at the bottom and is constantly removed as gaseous nitrogen, which has the lowest boiling point, comes off at the top of the column.
A labeled diagram would typically illustrate:
- The compression chamber where air is compressed.
- The fractionating column displaying the separation of gases at different levels.
- Outputs for gaseous nitrogen and liquid oxygen.
Step 3
Explain whether the fractional distillation of air is a continuous or a batch process.
Answer
The fractional distillation of air is a continuous process. In this method, air enters at one end and products (gases) come out at the other in a continuous manner. The process allows for the constant separation and extraction of various components without interruptions.
Step 4
Name and give one industrial use of a co-product of the fractional distillation of air.
Answer
One co-product of the fractional distillation of air is liquid nitrogen (LN2).
Industrial uses of liquid nitrogen include:
- Creating an inert atmosphere for processes like the freezing and preservation of food.
- Serving as a refrigerant in various applications such as cryogenics and laser cooling.