Why Are Hydrogen Peroxide Bottles Brown?

Most hydrogen peroxide sold to consumers comes in opaque brown bottles. Learn why in today's episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff from how Stuff Works, Hey, brain Stuff,
Lauren vocal bomb here. What do you get when you
combine two molecules of hydrogen and two molecules of oxygen, Well,
you get H two O two. More commonly known as
hydrogen peroxide, used in all kinds of industries from food
processing to papermaking, two textiles to electronics, peroxide is a

(00:24):
great disaffecting and bleaching agent. It's clear and colorless, and
when poured over an open wound, peroxide will kill many
types of microorganisms. It's also an extremely stable compound when
properly stored, which is why when you buy hydrogen peroxide
it usually comes in a brown plastic bottle. Here's why
many chemical compounds break down over time, and hydrogen peroxide

(00:48):
is no exception. Although it is extremely stable, the solution
can start to decompose when it comes in contact with
light and heat. The brown bottle in your medicine cabinet
is a bulwark against those two cattle lists. Light cannot
penetrate the tint of the brown bottle, preventing oxidation, which
you want to prevent because it can result in an
increase in temperature as peroxide breaks down. It gets hotter.

(01:11):
As a result, the compounds decomposition rate accelerates. In fact,
for every ten degree fahrenheit rise in temperature, the decomposition
rate nearly doubles, meaning that around seventy two degrees fahrenheit
that's about twenty two celsius, it decomposes at a rate
of one percent per year. But if it got up
to one fifty one degrees fahrenheit that's about sixty six celsius,

(01:32):
it would be decomposing at a rate of one percent
per week. By the time it hit the boiling point
of water, it would be going at nearly two percent
per day. Moreover, some sort of contaminants such as dust, silver, lead,
or another metal, gets into the solution, it can spark
a fire. Although the solution itself is not explosive. Those
in the industry must handle hydrogen peroxide with care. If

(01:55):
the solution is in a closed system, such as a
storage tank, and it starts to break down, press share
can build up, causing the tank or a pipe or
line to rupture. The good news is that the bottle
of peroxide in your medicine cabinet only contains about a
three percent solution, far less than that the food industry uses,
for example. You may also notice the peroxide never comes

(02:16):
in a clear glass container. That's because glass bottles may
contain dissolved alkali metal ions that can react with the solution.
Today's episode was written by John Paritano and produced by
Tyler Klang. Speaking of containers, you can find some with
the brainstuff logo and other designs in our online shop

(02:38):
at t public dot com slash Brainstuff, and of course,
for more on this and lots of other carefully handled topics,
visit our home planet, has stuff works dot com.