Redox

[Novex]

We just did a prac in class and our teacher gave us a few questions on it, this being one of the more "challenging" ones. After looking through my chem book, asking the (other) chem teachers and googling it I can't seem to find any information to help me answer this question.. :|

So I'm wondering if any of you guys might have any ideas on it?

  Quote

The relative ease of oxidation of the halogens is in this order: chlorine, bromine, iodine, with iodine the most easily oxidized. Design an experiment that would allow you to determine if the halogens are less or more easily oxidized than the metals used in this experiment (which were Copper, Lead and Zinc).

[Echilon]

I've only got up to GCSE level in chemistry, but can't you just put them in a box and let small amounts of oxygen in, then see which one oxidises first?

[Deryck]

With redox reactions occur as there is reduction and oxidation occuring at the same time. To remember which is which: oxidation is loss of electrons, reduction is gain of electrons, or OILRIG.

As to the experiment, we're looking at the oxidising power of the substance which is how much "power" they have to attract electrons to themselves.

I'm not quite sure with the methid but I've got two methods.

Method 1: With the experiement, we could use a control subatance such as potassium manganate(this may be a bit strong though) or lead sulphate or sulphuric acid and then add the substance you're testing (such as bromine, copper etc.) and add the two [e.g. copper and potassium manganate] in one test tube and observe the reactions such as colour change or smell etc. Do this with each substance you test and compare results to observe oxidation power. Potassium manganate would be good to use as it has a colour and a occurance of a redox reaction can be observed.

Method 2: React each of the halogens with each of the metals and observe and compare the chemical reactions to see what occurs when you react the two substances [e.g. a halogen and a metal] within a test tube.

Personally, I would prefer method 1.

Whatever method you choose, it would be helpful to buold a redox reaction using standard electrode potentials so to observe what would occur and to see the oxidation power of the substances. We can easily build this using reference books.

The image below describes of the reaction between bromine and potassium manganate. I had to alter the coefficients so to balance the two equations.

If you're going to use potassium manganate, then you would require it to be cool, diluted and have some acid added to it.

How to build electrode potential equations

Table of electrode potentials

Explanation of redox reactions

If you require help then contact me. :)

If there's a mistake above, then please PM me.