Which of the following industrial
processes does not involve fractional distillation? (A) Refining crude oil, (B)
separating gases in air, (C) making sulfuric acid through the contact process, (D)
extracting ethanol from a fermentation mixture.
Fractional distillation is a
technique that can be used to separate complex mixtures, and the components of the
mixtures can have boiling points that differ by less than 25 degrees Celsius. Fractional distillation also leads
to higher purity than simple distillation.
Crude oil, or petroleum, is a
complex mixture that can be separated using fractional distillation. During the refining process, crude
oil is passed through a fractionating column, which separates larger hydrocarbons
from smaller hydrocarbons to create more pure fuels. Fractions, such as gasoline, are
mixtures, not pure substances, and contain hydrocarbons with similar boiling
Fractional distillation can also be
used to separate air, which is a complex mixture of many gases. Fractional distillation makes it
easier to create pure gas products, such as nitrogen gas. Fractional distillation is also
used to extract ethanol from fermentation mixtures.
Ethanol has a boiling point of
about 78 degrees Celsius, which is very close to other liquids in the mixture such
as water, which has a boiling point of 100 degrees Celsius. The fractionating column used in
fractional distillation helps to ensure that the ethanol that is separated is as
pure as it can be.
When looking at the answer choices,
we now see that we can eliminate answer choices (A), (B), and (D), because these
processes do involve fractional distillation. This leaves only answer choice (C),
which must be our correct answer.
The contact process involves a few
steps. First, sulfur reacts with oxygen
gas to make sulfur dioxide. Second, sulfur dioxide gas reacts
with more oxygen gas in the presence of a catalyst to form sulfur trioxide gas, and
the reaction is reversible. Finally, sulfur trioxide gas reacts
with water to make sulfuric acid.
As we can see the making of
sulfuric acid through the contact process involves a series of chemical
reactions. On the other hand, refining,
separating, or extracting parts of a mixture through fractional distillation is a
physical process, not a chemical process.
In conclusion, the industrial
process that does not involve fractional distillation is making sulfuric acid
through the contact process, or answer choice (C).