Tlc Chemistry

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1. Which solvent or solvent mixture did you decide to use for your TLC? Why? The solvent we decided to use for our mixture was a 10 mL ethyl acetate with 10 mL of ethanol. We chose this solvent mixture because of the fact it brought out the most clear change on the TLC plate plus the solvent carried up the plate the fastest out of our 4 other mixtures. We needed these two things to get an accurate reading on our final.
2. Which pen matches the unknown ink? Provide a clear list of arguments as to why you believe it is a match. The pen that matches the unknown ink is the Sharpie. This is because in the final TLC plate, the Sharpie and unknown ink had a same number of Rf values, but the most obvious is that the colors and distance of the inks
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Four dots were marked along the horizontal line for the unknown ink and the three inks being tested to match the unknown ink: a Vis marker, Sharpie, and Just Basic marker. These inks were each individually put on different dots using a capillary tube, and the TLC sheet was then placed in the ethyl acetate/ ethanol solution in the same manner as earlier. After 3 minutes, the TLC sheet was removed from the solution, and a line was drawn along the solvent front for later identification. The Rf value was then calculated for each of the solutions pathing through the TLC sheet, using the equation Rf=Distance traveled by soluteDistance traveled by solute front. The Rf values for each of the inks were then compared with each other. Since the Rf values for the Sharpie matched those of the unknown ink, it was then determined that the Sharpie was the identity of the unknown ink.

Specific Results Obtained:

Figure 1. This TLC plate shows all inks in comparison with unknown ‘u’.

The figure above shows the final TLC plate with the inks given in comparison to the unknown ink. The unknown ink is in ‘u’, the Visavi is #1, Sharpie is #2, and the Just Basic marker is #3. The unknown ink was found to be Sharpie. The TLC plate was put into a solvent of 10 mL of ethyl acetate with 10 mL of ethanol.

Table 1. This table shows the Rf values for each ink.

Ink
Rf1
Rf2
Rf3
Rf4
Rf5
Unknown ‘u’
1 cm
0.5 cm
0.31 cm
0.16 cm
0.06 cm
Visavi #1
0.59 cm
0.4688 cm
0.44 cm
0.16 cm