How to determine saturation point of k2Cr2O7?

Answer 1

You need to know the solubility at various temperatures. Usually these values are available in the form of graphs or tables. If you don't have that information, you add, say 100 g K2Cr2O7 to 100 g H2O at say 25 C, let it dissolve as much as it will, filter, dry and weigh the amount that didn't dissolve. The difference is how much dissolved and that is the solubility in 100 mL H2O. Repeat for different temperatures.