why is a lid used in a chromatography experiment, and why do the colours travel different distances up the paper?
A top is used to keep evaporation of the solvent to a minimum. Different substances travel different distances because each substance has a different adsorbance to the stationary and moving phases.
Why is potespium is not kmnos his own indicator?
Because potassium permanganate has a deep violet colour which is highly visible to the naked eye and when one titrates it and there is a loss of colour, it is apparent. So one does not need an indicator to tell you the end point.
In a chromatography experiment, a lid is used to cover the container holding the chromatography paper and the solvent. This is done for a couple of reasons:
1. Preventing evaporation: The solvent used in chromatography experiments can evaporate over time, especially if left uncovered. The lid helps to maintain a constant level of solvent by reducing evaporation and ensuring that the experiment runs consistently.
2. Avoiding contamination: Keeping the container covered with a lid helps to prevent any foreign particles or contaminants from entering the system. This ensures that any differences in the color separation observed are solely due to the components being separated and not external factors.
Now, let's discuss why the colors in chromatography travel different distances up the paper.
Chromatography relies on the principle of differential migration, which means that different compounds have different affinities to the mobile phase (solvent) and the stationary phase (chromatography paper). The mixture being analyzed contains different components, and each component interacts differently with the paper and solvent.
As the solvent moves up the chromatography paper by capillary action, each component in the mixture will travel at a different rate. This occurs because the components in the mixture have varying degrees of attraction to the paper surface and the solvent.
Components that have a stronger affinity for the paper will adhere more strongly, resulting in a slower migration up the paper. Conversely, components with weaker interactions with the paper will travel faster with the solvent. This difference in migration rates causes the colors to separate and form distinct bands or spots along the paper.
Ultimately, the varying travel distances of the colors on the chromatography paper provide valuable information about the composition and properties of the analyzed mixture.