Liquid Conductivity

[seraphkz]

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Is a liquid ONLY conductive when there are IONs present? Or is a liquid conductive when there are polar molecules present as well?

Let's imagine a sample of pure water with no ion concentrations in it. Is it NOT conductive?


Thanks

 

[crazyasian]

pure water ionizes a very tiny bit, so technically its a little conductive (very little). But for the mcat I'd imagine that pure water is not conductive. And in regards to the question, I believe polar molecules won't make a liquid conductive unless it has a charge or can ionize. So yes for the mcat if there's not ions in the liquid, then unless the liquid itself can ionize, its not going to be conductive.

 

[ilovemcat]

In order for something to be "conductive" you need a current, and a current is defined as a flow of charge. A flow of charge (current) is often associated with metals ("a sea of electrons") since in metals, their valence electrons are free to float around. Another common example of a good conductors is an aqueous solution of a strong acid or base (lots of floating ions). Polar molecules aren't good conductors. Pure water is an example of a poor conductor.

 

[seraphkz]

Thanks guys!