Redox

[cobra]

has anyone ever done the redox lab with the iron nail and copper sulfate, adding the NaCl and water? i was wondering if anyone knows the products that are formed in the experiment... one is what is the green color in the experiment? and what is the yellow liquid at the top of the solution? thanks

[Ferdinand]

The green colour could be the result of the initial oxidation of iron atoms into iron II ions(green in solution) as copper II ions reduce to copper atoms. Some of the iron II ions will further easily oxidise to iron III ions(yellow to brown in solution - I like to call it "diarrhoea" coloured) as more copper II ions reduce to atomic copper. The NaCl simply dissociates and provides ions in solution to facilitate the charge flow and assists the previously mentioned redox processes to occur more efficiently. However, this is only one view of a possible mechanism. You may also want to read the thread "Nails in Copper II chloride...it is very enjoyable, in my humble opinion.

[cobra]

thanks for the info... i wasnt sure what everything was in that experiment. is the NaCl working as something called the salt bridge (heard about it). and btw, do you know if the iron (III) ions float on the surface of the solution... also, there seems to be a dullish pink substance below a layer of my NaCl that is left and copper and sulfur (i believe).. any ideas of what it may be?

[cobra]

so.... when you said that the green is probably the iron(II) ions... can it not be FeCl2? or FeSO4 after the redox reaction between Fe, CuSO4, and H2O and NaCl... and you also said that the yellowish brown liquid is iron(III) ions....is it not FeCl3? thanks

[woelen]

has anyone ever done the redox lab with the iron nail and copper sulfate, adding the NaCl and water? i was wondering if anyone knows the products that are formed in the experiment... one is what is the green color in the experiment? and what is the yellow liquid at the top of the solution? thanks

Could you please be more specific in your description. If you want an adequate answer, then your description must be precise.

 

1) Give a precise description of the procedure. Give the order in which chemicals are added. Also give an indication of the amounts added.

2) State precisely which color is observed during which stage of the experiment. Also try to describe the colors precisely. There are many shades of green, like bluish green, bright green like grass, but also muddy green/brown colors.

 

There are other threads on this subject on SFN, which are of very recent date. Just look a little further in the existing threads of the chemistry section.

 

Especially this topic may be very helpful: http://www.scienceforums.net/forums/showthread.php?t=17423

 

But it is also a good idea to read this one:

http://www.scienceforums.net/forums/showthread.php?t=15956

 

Next time: UTFSE

[cobra]

first, the CuSO4 crystals were added to the test tube... afterwards, a paper circle(filter paper) was added and the tub was filled with water up to CuSO4... then, NaCl was added (4-5 g) and then filter paper was placed on top, along with addition of water.... on top was the iron nail, and then the tube was filled with water.... on 2nd day, i noticed a yellowish-brown solution near the top and then a light greenish solution in the middle... the bottom had a black substance.. the nail rusted and Cu (s) was observed... also, yellow precipitates were observed...... what would each color be, esp the yellow precipitate, the yellow solution, and green solution...