Electrolysis Experiment Help! URGENT?

Question

I'm doing an electrolysis experiment. I have one jar (4 Litres of water) and have placed 2 copper electrodes in the jar. I added 5% salt to the water. I filled 2 test tubes to the top with water, covered the top and submerged it in water over the electrodes. I'm using a DC power supply. For some reason the water in the test tube connected to the negative end of the power supply is dropping dramatically, therefore it must be producing hydrogen (I checked this with a 'pop' test). However, the water connected to the positive end (anode_ of the power supply hasn't dropped at all. And aren't I meant to see a 2:1 ratio. I also noticed that the water was turning to a bluish greenish colour. I reduced the sodium chloride concentration to approx. 1.7%. However, still no oxygen was produced. Could someone please help me. If you have further questions, you may email me. This is urgent, so could someone please help me.

I don't really want to change my copper electrode. Is there another solution to the problem (the same thing was happening when I used pencils - no oxygen was produced, the only difference was that the water was like an orange/red colour.

Answer 1

You really need to change the electrodes, however instead of using pencils for carbon/graphite, you can get reusable, and much larger rods out of "Heavy Duty" or "Carbon-Zinc" AA, C and D batteries. Make sure the battery is one of these types. Alkaline batteries will have a metal nail instead of the carbon rod, and some 9-volt batteries have no rods whatsoever.

Carbon electrodes are really superior, as they won't react with your solution like metals will. Also, carbon rods, even if they feel smooth, are incredibly porous, which greatly increases the surface area of the electrode, allowing faster production of the gases. Plus, you can get two big rods from a 2-pack of generic D-cell batteries for as little as $0.99 from any dollar store.

Answer 2

Off the top of my head, I would guess that the oxygen is combining chemically with the copper in the wire (copper oxide is green).

Try using something like an unbent steel paper clip, rather than a copper wire.

Answer 3

hi! The relative atomic weight of Cu is sixty 3.546, of Ti is 40 seven.88. So the 'quantity' in 16g of Cu is 0.2517 unit, in 6g of Ti that is 0.1253 unit. this way the Ti must be charged 2 situations the Cu. The oxidation steps of copper: Cu, Cu+ and Cu2+. The oxidation steps of titanium: Ti, Ti2+, Ti3+. The +4 isn't allowed for the titanium, so i think of the fee on the Cu became +a million, and on the Ti it became +2.