Question

Topic : Solubility in a supercritical Fluid.
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At constant density, solubility will increase with temperature. However, close to the critical point, the density can drop sharply with a slight increase in temperature. Therefore close to the critical Temperature, solubility often drops with increasing Temperature, then rises again.
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Explain this passage with graph if possible.
Give reason why solubility close to critical point often drops but then again increases.
Relevant answer is required.
Inexperienced guys kindly don't answer.

Answer 1

At critical point the substance does not exist in either the liquid or gas phase. under this condition it is called superficial fluid and has a properties between those of liquid and gas. In close to the critical point small changes in pressure and temperature result in a large change in the density. Allowing many properties of a supercritical fluid to be fine-tuned. Solubility in a superficial fluid tends to increase with densityof a fluid at constant temp. since density increase with pressure, solubility tends to increase with pressure.

However relationship with temperature is more complicated. At a constant density, solubility will increase with temperature. Moreover , close to the critical point the density can drop sharply with a slight increase in temperature.Therefore close to the critical temperature, solubility offen drop with increasing temperature, then rise again.