Video Transcript
What type of filtration would the
apparatus shown in the diagram be used for? (A) Centrifugal filtration, (B)
gravity filtration, (C) multilayer filtration, or (D) vacuum filtration.
Filtration is a separation
technique that can be used to separate an insoluble solid and a liquid. To answer the question, we need to
determine which of the four types of filtration listed can be performed using the
apparatus shown.
To perform centrifugal filtration,
we need to use a centrifuge. A centrifuge spins the mixture at
high speeds, which forces the solid component of the mixture to the bottom of the
test tube. As the diagram does not contain a
centrifuge, we can eliminate answer choice (A).
To perform gravity filtration, a
piece of filter paper is placed inside of a funnel that is suspended above an
Erlenmeyer or conical flask. When a mixture is poured into the
filter paper, large solid particles will be trapped by the filter paper, while
liquid molecules, dissolved ions, and any small particles able to pass through the
filter paper will be dropped into the Erlenmeyer flask due to gravity.
The setup shown here appears to
match the diagram shown. So it seems that gravity filtration
is the correct answer. But just to be sure, let’s take a
look at the remaining answer choices.
Multilayer filtration, as the name
suggests, uses multiple filters. It is a more complex method of
filtration that can be used to separate a liquid containing many different
solids. The apparatus shown in the diagram
only appears to contain one filter paper, not many layers of filters. As such, we can eliminate answer
choice (C).
To perform vacuum filtration, a
piece of filter paper is placed inside of a Büchner funnel, which is attached to a
Büchner flask. The side arm of the Büchner flask
is attached via thick-walled tubing to a vacuum line or aspirator. With the vacuum or aspirator on,
the mixture is poured into the Büchner funnel. As with gravity filtration, any
large solid particles will be stopped by the filter paper inside of the funnel,
while any liquid molecules, dissolved ions, or particles small enough to pass
through the filter paper will be pulled into the flask. The primary difference between
gravity and vacuum filtration is the force used to separate the mixture. Gravity filtration relies on the
force due to gravity, while vacuum filtration relies on suction. As the diagram provided does not
show a Büchner flask, Büchner funnel, or vacuum line, we can eliminate answer choice
(D).
Therefore, we can be sure that the
type of filtration that the apparatus shown in the diagram can be used for is
gravity filtration, answer choice (B).
