Reporting and Presenting LLE Data

The most common way of reporting and presenting two-species LLE data [ 1 ] is as a table like Table 11.1. Although [ 1 ] presents solubilities in mol percent, which we mostly use in this chapter many sources [2] present them as weight percent. From Table 11.1 we see that both solubilities increase slowly with increasing temperature. The effect of temperature on solubility is discussed in Section 11.2.6. We also see that the solubility of benzene in water at 25°C is 0.0405 mol% = 0.000,405 mol fraction = 405 ppm by mol. This is practically insoluble.  

Example 11.1 A common way to measure small solubilities like those shown in Table 11.1 is to add one species from a buret, one drop at a time, to a large mass of the other species. After each drop is added the mixture is shaken and observed to see if it has turned cloudy, indicating that the solubihty limit has been reached. If we begin with 1L 

Typically a buret will deliver about 20 drops of liquid per milliliter, so for benzene 

We are all familiar with the expression water and oil don t mix. From this example and from Table 11.1 we would conclude that since benzene is an oil, the expression should reaUy be water and oil don t mix very much.  

Example 11.2 One thousand pounds of benzene have been leaked into the soil, in contact with the groundwater. The benzene slowly dissolves in the groundwater. How many pounds of groundwater will become saturated with benzene  

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