Today’s lab had a catch to it; it’s didn’t smell too well. But that was no problem, as our group quickly set up six test tubes. Three were filled with water, and the other three with turpentine (paint thinner). Why did we set this up? Well, we wanted to know if glycerin is polar or non-polar.
We added table salt to a test tube AW (water) and to AT (turpentine). We did the same with sugar and crystals of iodine. What did we notice after some shaking? Well,
Table Salt and sugar both dissolved in water, whereas iodine (I2) did not.
Iodine dissolved in paint thinner, whereas table salt and sugar did not.
We knew that water was polar and that turpentine was non-polar. In addition, we knew that table salt and sugar were polar and iodine was not. Therefore, since polar substances dissolved only in polar substances, we knew there was a connection. In addition, since non-polar substances dissolved only in non-polar substances, we discovered what was going on.
Like dissolved Like. Polar dissolves polar; non-polar dissolved power.
With this power in hand (knowledge is power), we set off to find out whether glycerin is polar. After adding it to water and shaking, it dissolved. Therefore, it was polar. We could have further explored this, but the turpentine ran out. But we can imagine what would happen. Since turpentine is non-polar, and glycerin turned out to be polar, then glycerin would not dissolve in the turpentine.
As we learned from the lab, only ‘like dissolves like’. Therefore, unless the mixture above is stirred, the two non-polar substances cannot come into contact and will remain separated by the polar substances.
And as a first for this blog, we have a video that directly corresponds to the picture:
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