12.24. Explain the principle of paper chromatography.
In paper chromatography, chromatography paper is used. It contains water trapped in it, which acts as the stationary phase. The solution of the mixture is spotted on this base of chromatography paper. The strip of paper is suspended in a suitable solvent, which is the mobile phase. Due to capillary action, the solvent rises up in the paper and it flows over the spot. The spots of the different component travel with the mobile phase to a different level of heights. The obtained paper is called chromatogram.