Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: redpower on October 15, 2010, 11:21:01 PM
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I have just carried out a lab experiment today and really need some assistance.
The Experiment:
In my experiement I attempted to mix a solution of hexane with aqueous bromine. I started off by adding 15 drops of bromine into a test tube and then added 7 drops of hexane ontop of that. Prior to shaking, I could see two distinct colours in the test tube separated by a meniscous: the yellow bromine liquid lied at the bottom and the clear + colourless hexane solution lied on top of the bromine. After shaking, something odd happened. The two layers switched places => bromine ended up on top and hexane resided at the bottom of the test tube. The two colours were still distinct and separated by a meniscous. (The same thing happened when I tried to mix toluene with bromine)
What Happened?
Seeing that these two solutions would not dissolve each other, I concluded that one of them must be polar and the other must be non-polar. (We have previously learned that only "like dissolves like") HOWEVER, after analysing the substances, I realized that hexane (a hydrocarbon) and bromine are BOTH NON-POLAR SUBSTANCES. If that is the case, they should have dissolved each other - but they didn't! Thus, I am in a dilemma right now and have no idea how to approach this lab.
Any help would be greatly appreciated! Thank you in advance!
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Are you sure LAYERS switched place? If you started with 15 drops of water and 7 drops of hexane, one of the layers was twice as thick as the other, so they can be easily recognized.