Consider the following errors that could be made when running TLC. Indicate what should be done to correct the error.

a) a two-component mixture containing 1-octene and 1,4-dimethylbenzene gave only one spot with an Rf value of .95. The solvent uses was acetone.
b) a two-component mixture containing a dicarboxylic acid and tricarboxylic acid gave only one spot with an Rf value of .05. The solvent used was hexane.
c) when a TLC plate was developed, the solvent front ran off the top of the plate.

a) use a less polar solvent.

b) use a more polar solvent
c) develop more quickly (less time to run the separation).

b use a more polar solvent

a) In the case of a two-component mixture containing 1-octene and 1,4-dimethylbenzene, if only one spot with an Rf value of 0.95 is obtained, it suggests that both compounds have similar affinities for the stationary phase and are not well separated. To correct this error, a more polar solvent can be used to increase the separation between the two compounds. Acetone is a relatively non-polar solvent, so choosing a more polar solvent such as ethyl acetate or methanol may improve the separation.

b) In the case of a two-component mixture containing a dicarboxylic acid and tricarboxylic acid, if only one spot with an Rf value of 0.05 is obtained, it suggests that the compounds are strongly retained on the TLC plate and not effectively migrating with the solvent front. To correct this error, a less polar solvent can be used to increase the mobility of the compounds and improve their separation. Hexane is a relatively non-polar solvent, so choosing a less polar solvent such as dichloromethane or toluene may help improve the separation.

c) When the solvent front runs off the top of the TLC plate, it suggests that the TLC plate was overdeveloped. This typically happens when the solvent is allowed to travel too far up the plate. To correct this error, the development of the TLC plate should be stopped earlier by removing it from the developing chamber before the solvent front reaches the top of the plate. This can be done by visually monitoring the progress of the solvent front and taking the plate out at the desired separation and visualization of the spots.

a) In this case, the Rf value suggests that both 1-octene and 1,4-dimethylbenzene had similar levels of affinity for the stationary phase on the TLC plate. Since they have different chemical structures, they should have different Rf values.

To correct this error, you could try using a different solvent system which provides better separation between the components. Acetone might not be a suitable solvent in this case. You can try using a different solvent or a combination of solvents which better match the polarity of the compounds being separated.

b) The Rf value of 0.05 suggests that both the dicarboxylic acid and tricarboxylic acid had low affinity for the mobile phase and high affinity for the stationary phase of the TLC plate. This indicates that the chosen solvent (hexane) was not polar enough to adequately separate the two components.

To correct this error, you could try using a more polar solvent or a combination of solvents that are more polar. Adding a small amount of a polar additive (such as a few drops of acetic acid or methanol) to the hexane solvent may also help improve the separation.

c) When the solvent front runs off the top of the TLC plate, it means that the solvent used for development was too polar or the TLC plate was not properly set up. This could result in poor separation and inaccurate Rf values.

To correct this error, you need to ensure that the TLC plate is set up properly. Make sure that the plate is saturated with the solvent in a developing chamber by adding some solvent to the bottom of the chamber and covering it with a watch glass or lid to create a closed system. The solvent vapor will then rise up and saturate the TLC plate evenly.

Additionally, you can try using a less polar solvent or a different solvent system that matches the polarity of the compounds being separated. Adjusting the polarity of the solvent can help prevent the solvent front from running off the top of the plate and provide better separation for accurate results.