Why is adsorption phenomenon always exothermic?

What does Kp mean? gorganic layer gwater layer Kp = all choices are correct it is the equilibrium constant that describes the partition coefficient between the two layers it is the equilibrium constant that describes the distribution of a molecule(s) between two layers it is the equilibrium constant that describes the molecular migration between the two layers

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The band gap of gallium phosphide is 2.26 eV, which makes it appropriate for producing yellow LEDs, although the yellow color is rarely useful on its own (think a yellow laser pointer). One can alter the band gap of GaP, changing the emission color to red or green. Propose the ways to produce these two colors by (1) chemical (compositional) and (2) physical (non-compositional) modifications of the material.