Ions dissolved in water

Rose2000

Hi. I was looking through a chemistry book and I came across the idea that ions, when dissolved in water, conduct electricity. It never explained how this allows electrons to be transferred, as a result, to the other electrode and I would be so grateful if anyone could explain... Do the ions act like capacitors or is it something else? Thanks

bduffy

Rose2000 wrote: »

Hi. I was looking through a chemistry book and I came across the idea that ions, when dissolved in water, conduct electricity. It never explained how this allows electrons to be transferred, as a result, to the other electrode and I would be so grateful if anyone could explain... Do the ions act like capacitors or is it something else? Thanks

When something like a salt dissolves in water it dissociates (breaks up) into a cation and anion. These are charged positive and negative respectively. When you put a pair of electrodes in the water and put a voltage across, the cations move to the cathode and anions to the anode. This creates a current, defined as the movement of charge. This is how electroplating works, think of Newbridge Cutlery and their finish. For electrons to be involved you need something to donate them and this would be oxidation and reduction chemistry (think of Iron rusting which is an oxidation process). Metal become metal ion plus electron.... but using oxygen.....

Rose2000

Thanks for your reply. It's very helpful. If the salt you dissolve was something like sodium flouride (NaF) or magnesium oxide (MgO) or basically any ionic substance where the anion is one of flourine, oxygen or nitrogen, are hydrogen bonds formed between the hydrogen in the water molecule and the anion? If so would the conductivity be affected? If not is there a reason why? Thanks again.