Is Water Non-Conductive? Exploring Ions & Electricity

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In summary: After that, the water is back to being just water. So, over time, some of the H3O+ ions will dissociate and the water will become more acidic or alkaline, but it's a very slow process.
  • #1
KingNothing
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I understand water in its purest form is non-conductive, or something like that.

I also know that there will always be some ions no matter how clean the water is...what kind of ions are these?

Are they enough to actually make it, say, carry some voltage a few inches and light a light bulb or something like this?
 
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  • #2
KingNothing said:
I understand water in its purest form is non-conductive, or something like that.
If,by non-conductive, you mean "a very poor conductor", then yes, this is true.

I also know that there will always be some ions no matter how clean the water is...what kind of ions are these?
[itex]H^+~and~OH^- [/itex] ions.
There will be about [itex]10^{-7}[/itex] moles (or about [itex]3.3*10^{18} [/itex] ions) of each kind, per liter of water. This is actually a very small number.

Are they enough to actually make it, say, carry some voltage a few inches and light a light bulb or something like this?
I would have to say no. The resistivity of pure water is about 18 megaohm-cm. This is a really large number. You can make the resistance a manageable number but it would take a crazy geometry (extremely small L/A) and large electrodes, and of course, an AC source. At a length of "a few inches" you will need an area of several squre miles, I presume (but haven't really calculated).
 
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  • #3
KingNothing said:
I understand water in its purest form is non-conductive, or something like that.

I also know that there will always be some ions no matter how clean the water is...what kind of ions are these?

Are they enough to actually make it, say, carry some voltage a few inches and light a light bulb or something like this?

Yes, pure water is a very poor conductor. Every year the students here have to build a radio receiver, one year one group built their radio circuitry immersed in de-ionised water. It looked spectacular.
 
  • #4
So there won't be any H3O ions?
 
  • #5
cosmik debris said:
Yes, pure water is a very poor conductor. Every year the students here have to build a radio receiver, one year one group built their radio circuitry immersed in de-ionised water. It looked spectacular.

And for how long did it work as pure water is also very aggressive and will disolve some of the metal i.e of the copper conductors, lead/tin etc and the resistivity would immediately drop.

For this reason you will not find de-ionized water being piped in metal pipes
 
  • #6
Why does the hydrogen not escape? If a certain % of weater is ionized as H and OH, won't some of the H be lost? I realize that, bering ionized, it will tend to stay with the OH molecules, but I would have thought that some would effectively "evaporate" over time, and an overwise undisturbed volume of water open to the air would eventually become (acidic? alkaline? I always forget which is which).
 
  • #7
AntonVrba said:
And for how long did it work as pure water is also very aggressive and will disolve some of the metal i.e of the copper conductors, lead/tin etc and the resistivity would immediately drop.

For this reason you will not find de-ionized water being piped in metal pipes
I can't imagine they kept under DI for very long. You're absolutely right...copper will start corroding pretty fast in DI.
 
  • #8
DaveC426913 said:
Why does the hydrogen not escape? If a certain % of weater is ionized as H and OH, won't some of the H be lost? I realize that, bering ionized, it will tend to stay with the OH molecules, but I would have thought that some would effectively "evaporate" over time, and an overwise undisturbed volume of water open to the air would eventually become (acidic? alkaline? I always forget which is which).
Actually, the H+ ions attach themselves to H20 molecules (through a version of the hydrogen bond), forming H3O+ ions (as KingNothing mentioned above).
 
  • #9
Gokul43201 said:
I can't imagine they kept under DI for very long. You're absolutely right...copper will start corroding pretty fast in DI.

That's right, they only have to demonstrate the thing in front of a class for a few minutes or so.
 

Related to Is Water Non-Conductive? Exploring Ions & Electricity

What is water conductivity?

Water conductivity refers to the ability of water to conduct electricity. This is due to the presence of ions, which are charged particles, in water.

Is water non-conductive?

Pure water, without any added ions, is non-conductive. However, most water sources contain some level of dissolved ions, making it conductive to varying degrees.

What are ions?

Ions are atoms or molecules that have a positive or negative charge due to the loss or gain of electrons. In water, ions can be present as a result of dissolved salts or other substances.

How does the presence of ions affect water conductivity?

The presence of ions in water allows it to conduct electricity. This is because ions are free to move and carry electrical charge through the water. The more ions present, the higher the water's conductivity will be.

What factors can affect water conductivity?

The conductivity of water can be affected by various factors such as the temperature, pH level, and the type and concentration of dissolved ions. For example, warmer water tends to be more conductive than colder water, and highly acidic or basic water can also have different conductivity levels.

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