Helllo

I have a question here about electrolic sollution (like NaCl dissolved in water......... duh, wish I had taken an English Chemistry class...).
Let's say I had a big tank of NaCl sollution, and I were boiling it. At the same time, I dipped 2 electrodes (carbon, metals, whatever.....) which are connected via a cable with an Amperemeter and a bulb (unnecessary). The bulb should light up or the Ampmeter reading should rise, correct? If I were to boil the sollution til it's dried up (i.e: no water):
1) How would the electric current reading look like? Constantly rose, constantly fell, rose and fell slowly or rose to a point where it suddenly fell to zero?
2) Would there be anything left in the tank? Sodium? Chlorine? NaCl?

Thanks

I don't know, I think this is an experiment you should try. Get a voltmeter and boil some salt water. Post the results :)

Assuming the solution is not saturated (holding all the salt it can) at boiling temp, then the following should happen:

As the water boils away it leaves the NaCl and the concentration of the solution goes up, as does the conductivity and the amperage.

At a certain point, the solution will hold as much NaCl as it can and as the water boils it will percipitate out. the conductivity and amperage will remain constant.

As the water continues to boil, less and less of the electrodes will be submerged and since current flow also depends on the cross section area of the conductor, the amperage will slowly start to drop until it reaches zero once the last of the water boils away and you are left with nothing but NaCl.

This is assuming that the NaCl does not precipitate out onto the electrodes themselves and form a non-conducting barrier. In this case, the current will drop off before all the water boils away.

Sodium chloride

Boiling Point:
1413C (2575F)
Melting Point:
801C (1474F)

The melting point of glass is between 800 degrees Celsius and 950 degrees Celsius and its tensile strength resides almost entirely on its outer skin. Glass does not have a fixed melting point; it grows soft and increasingly liquid as temperatures rise. Sudden rises in temperature can engender different effects than gradual increases.

As the water boils away it leaves the NaCl and the concentration of the solution goes up, as does the conductivity and the amperage.



Where does that amperage come from? In the expt as described, Curiocity says using electrodes (not specifying different metals, btw). He doesn't say to supply a current, and different metals would be required to produce a battery effect. However I wouldn't expect a current with different metals anyway (and in fact just dunked some copper and aluminium electrodes into some hot saline and got no voltage or current) as the Sodium is going to be the most reactive element in the system, already a salt, and therefore no ion transfer will take place, and therefore no current will be generated.

If a current were supplied, things will go as you stated of course.