Ion Distribution in Grounded Metal Bowl: NaCl in Water

[patm95]

Homework Statement

Imagine water in a metal bowl that is open to air. This metal bowl is grounded. You add some NaCl to the water. What would the distributions of the ions look like in the water.

Homework Equations

I think this doesn't need equations, but just general understanding of how ions interact with each other and conductors.

The Attempt at a Solution

My thought process is this. If the NaCl ions could combine in water, then they wouldn't dissolve. So we have these ions floating around which increase the conductivity of the water. Because the metal itself is grounded and also a good conductor we get somewhat of a image effect in which the ions will tend to collect towards the metal bowl. Is this a good understanding of the problem?

 

[Coto]

Sounds somewhat close. You are definitely right on the reason NaCl dissolves. NaCl dissolves in water to form aqueous Na+ and Cl- ions.

Now on the next part I'm not so sure. Why would any image effect be produced? Realistically you have equal numbers of positive and negative charges randomly floating around. Any effects produced by a positive ion will be canceled by the effects of a nearby negative ion. Although the bowl is grounded, you would still need to add an electrode to the solution in order to induce any structural form of ions.

This is my opinion though... take it with a grain of salt ;)