Consider the following errors that could be made when running the TLC. Indicate what should be done to correct the error.
a) A 2 component mixture containing 1-octene and 1,4- dimethylbenzene gave only 1 spot with and Rf value of 0.95. The solvent used was acetone
b) A 2 component mixture containing a dicarboxilic acid and tricarboxilic acid gave only 2 spot with an Rf value of 0.05. The solvent used was hexane
c) when a TLC plate was developed the solvent ran off the top of the plate.
[b]
a) I think that the compounds are nonpolar while the solvent is polar thus that led to bad seperation. And the solvent was of high polarity.
b) For this one I think that the reason there is bad seperation is that the compounds are polar while the solvent is nonpolar. The solvent has a low polarity thus it doesn't separate well.
c) I think for this one all the person has to do is take out the the plate before the solvent gets that far
Thanks Is my thinking correct?
I forgot to say how to fix it
a)for a where the solvent is highly polar thus pulling all the solvent with it..I think you can add a solvent of less polarity but rather intermediate polarity
b) I think for this one you can add a solvent with intermediate polarity of course higher than the polarity of hexane.
Your thinking is partially correct, but let's analyze each error individually and provide the appropriate corrections:
a) A 2-component mixture containing 1-octene and 1,4-dimethylbenzene gave only 1 spot with an Rf value of 0.95. The solvent used was acetone.
In this case, the error is most likely due to the solvent choice. Acetone is likely too polar to separate these nonpolar compounds effectively. To correct the error, a less polar solvent, such as hexane, should be used to improve separation.
b) A 2-component mixture containing a dicarboxylic acid and tricarboxylic acid gave only 2 spots with an Rf value of 0.05. The solvent used was hexane.
Here, the error is related to the solvent polarity relative to the compound polarity. Since both acids are likely polar, a nonpolar solvent like hexane might not be ideal for separation. The correction would involve using a more polar solvent, such as ethyl acetate or a mixture of ethyl acetate and hexane, to improve separation.
c) When a TLC plate was developed, the solvent ran off the top of the plate.
In this case, the error lies in the incorrect setup of the TLC chamber or the improper positioning of the TLC plate. To correct the error, the person should ensure that the TLC plate is placed properly in the chamber, ensuring that the solvent level is below the starting point of the compounds on the plate. This can be done by not overfilling the chamber with the solvent or using a smaller TLC plate.
Overall, your initial understanding is correct, but it's important to consider the polarity of compounds and solvents when working with TLC.