True or False: A sample that aspirin has an $R_f$ worth of 0.20 when measured ~ above a silica gelatin TLC plate v a specific solvent mixture. If the polarity that the solvent is increased, the $R_f$ value of the aspirin will come to be larger.

Would this it is in false? because aspirin is polar (I think would be considered polar due to the fact that it dissolves in water regardless of some various other sources saying that it is actually non-polar) and the silica in the TLC plates are likewise polar, aspirin would not be able to travel an extremely far since it would interact with the silica. Thus, shorter distance over much longer distance = reduced $R_f$ value, through $R_f$ = distance spot moves/ street solvent moves.

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I wish we would avoid teaching chromatography in regards to "polar" and "nonpolar."

The aspirin will interact relatively strongly v the silica because of hydrogen bonding/electrostatic interaction of the carboxylic acid and also the ester through the silica. If you increased the "polar" component of the mobile phase, the would take trip further because of the mobile phase competing much more for binding spots of the silica gel.

So increasing the polarity the the mobile phase does progressive $mathrmR_f$ the aspirin (or anything) on constant silica gel.


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Since aspirin has actually a carboxylic acid group on it, it would be taken into consideration polar. Silica gel, consists of $ceSiO2$, is likewise polar. Due to the fact that polar molecules entice other polar molecules, the aspirin molecules will often tend to bind to the silica and not relocate up the TLC plate in a nonpolar eluent, bring about a short $R_f$ value.

When the polarity the the eluent is increased, its capability to entice polar molecules is increased. This means that it can far better compete with the silica in attracting the aspirin, and also the $R_f$ value will it is in higher.


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