Mothball Effectiveness and Ingredients
Name: Nicole P.
What property of paradichlorobenzene makes it an effective ingredient in
Paradichlorobenzene (a chlorinated aromatic hydrocarbon) is not the stuff of which moth
balls are made. Paradichlorobenzene is referred to as "moth crystals." Moth balls are
composed of naphthalene, which is a also an aromatic hydrocarbon. "Aromaticity" in this
context refers to molecular structure, not odor -- although both compounds have powerful
Under room temperature conditions, these solid chemical compounds have a relatively high
vapor pressures. They can sublime directly from the solid to the gaseous state without
melting during the phase change. When they do, they displace oxygen from confined spaces.
Thus, one of their insecticidal properties is that of suffocation -- they deprive bugs of
air. Also, their chemistry is incompatible with living systems -- they are toxic.
Usually the commercial type mothballs are made of either naphthalene or para
dichlorobenzene. Both these substances are toxic to moths that can destroy clothes kept
in closed places. Besides that they can sublimate, that is they go directly from the
state to the gas state. As gas they can go inside clothes and fill the place where they
stand, killing the moths if they are there.
Be careful when using any kind of moth balls, they are also toxic to humans and pets.
Mostly never use in children closets or keep them in places where a child can find, play
or even put in the mouth. Moth balls are poison!
And thanks for asking NEWTON!
(Dr. Mabel Rodrigues)
Paradichlorobenzene along with naphthalene make a good insecticide because both compounds
sublime quite readily in the open atmosphere.
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Update: June 2012