Napthalene, those white, tablet shaped balls with an amazing smell (Well, atleast for me) have been used for many years to keep insects like cockroaches and moths away. Just toss some into a closed area and it will be insect-free until the ball sublimes. However, not many know as to why this substance has insect repellant properties. This is our topic for today.

Napthalene is a hydrocarbon i.e. it is completely made of carbon and hydrogen. Its chemical formula is C₁₀H₈ . It has the property to sublime i.e. to convert to the gaseous state from the solid state, bypassing the liquid state (If you want to know why substances sublime, check this article of mine- https://pcbpedia.home.blog/2019/10/19/why-do-substances-sublime/).

Napthalene can kill humans too if they are exposed to it for a long time, or if they ingest it. Now, let us see why insects are repelled by napthalene.

Considering the example of a cockroach, they too have a respiratory system like we do. Now, the fumes that are emitted by napthalene tend to block a cockroach’s respiratory tract, also called as tracheae. These fumes tend to disrupt the metabolism of the cockroach and start to suffocate it. As a matter of fact, napthalene is also used in the manufacturing of PVC (PolyVinyl Chloride), which is a very durable type of plastic usually used in making plastic carry bags. So, you can imagine how poisonous it could potentially be. In certain species, it is even known to be carcinogenic (cause cancer).

So, as the cockroach knows it is poisonous and that it might suffocate, it stays away. However, if it is trapped, it will succumb to the fumes, though we rarely see cockroaches lying dead near napthalene.

Coming to the other effects of napthalene, it has been known to cause a variety of dosorders like haemolytic anaemia, jaundice, nausea, diarrhoea among others.

So, how was it? Did it make you throw napthlene balls all over the place? Feel free to comment in the Comments section down below.

Stay Home, Stay Safe!

Note: This might be my shortest article I have written. Don’t worry, as longer articles are on the way.

Author: Venkata Bhamidipati.