The Kipp
generator
was invented in 1844 by Petrus Jacobus Kipp and used throughout the
rest
of the 19th and the entire 20th centuries. Indeed, Kipp
generators
are still being used in some places. When qualitative analysis
was
taught to all students of chemistry, the Kipp generator was used to
provide
hydrogen sulfide for determination of specific metal ions.
Left: A Kipp
40-cm
tall generator being filled with zinc chunks. Right: A line
drawing
showing the general design of a Kipp generator. The zinc goes in
the gas reservoir and is prevented from falling into the lower base by
the conical piece of glass with the small holes (the inner separator).
Here Kayla uses a
glass
stir rod to position the zinc evenly around the cone-shaped inner
separator
The acid
reservoir
will eventually contain the acid used in the reaction. Notice
that
the long glass tube passes through the center of the inner separator
and
will deliver the acid directly to the lower base chamber. (See
line
drawing above.)
Another view of
Kayla
positioning the acid reservoir. At right, drawing shows the
location
of the zinc relative to the inner separator and acid reservoir.
Next the 1 M HCl
is
added. The gas reservoir (the middle chamber) is a closed system
and the air pressure prevents the acid from draining down into the
base.
At this point the acid and zinc have not come in contact.
Kayla releases
the
hemostat and the air rushes out of the gas tube allowing the acid to
drain
from the upper (acid) reservoir to the base chamber. Things are
getting
exciting!
These two
drawings
explain the action! Because the hemostat is removed, gas is
jetting
out of the gas tube. This allows the acid to drain from the acid
reservoir to the base chamber. The acid level rises in the base
chamber
and (right) eventually starts to pass through the holes in the inner
separator
where it reacts with the zinc. Now hydrogen is being generated
and
will start issuing from the gas tube. (The gas reservoir
initially
contained air which is quickly displaced by the hydrogen.)
Hydrogen
displaces
water in a jumbo test tube (300 mL) within seconds!
By clamping the
gas
tube, (1) delivery of hydrogen stops, (2) the pressure inside the gas
reservoir
builds up which (3) forces the acid back out of the gas reservoir and
into
the base chamber and (4) back up into the upper acid reservoir!
When
the acid and zinc are no longer in contact, the generation of hydrogen
ceases.... until someone opens the gas tube again! Hydrogen is
'on
tap.'
Here Kayla and
Scot
fill one of our 60-mL syringes -- old meets new!
Here is a larger
(62
cm) Kipp generator which arrived at Creighton on Halloween (which
explains
why Kayla looks the way she does, but does not explain Mattson's
appearance!)
We have not fired the big one up yet! Left is Professor Bruce
Mattson
in his lab and right is Kayla Pound, a Creighton chemistry major.
Her research on generating gases in a microwave oven is published in
Chem13
News and available at this site.
Special thanks! Bruce Mattson would like to thank Ron Perkins of Educational Innovations for his kind gift of the two Kipps generators. Be sure to shop his store (Educational Innovations) for all of your science needs!
