Question

3. The value of AG that you determined for the dissolution of borax at 25°C should be positive (if not you should check your work). Given that AG >0, how do you explain that some of the borax actually dissolved at 25°C?

Answer 1

borax is more soluble in hot water than cold water. hot water holds more borax crystals than cold water. the solubility of borax in water increases as the temperature increases. more borax is dissolved at high temperature implies that heat is also a reactant here. and solvation of borax is a endothermic reaction.

H₂O then the amount borax (aq) actually [bopax] () of borax that can be dissolved at a constant Ksp = [borax] we will means when is cor some borax if, Some that the equlibrium is attained precipitated out. this amount of boray As dissolution of borax needs heat, so, at 25° water evaporated the axequlibrium is disturbed. concentration of the dissolved w would increase However the solution is already satwiated , now the concentration a exceed the value of Ksp (Aspy Ksp). To retain the equlibrium borax must precipitate out and the equlibrium shifted to the left side 'according f. dissolved some dissolved to Le châtelier principle.

∆Grxn ​​​​​​0 > 0 also implies that it is a endothermic reaction at 25° C.

now we know that when we add any substance (say borax), borax has a maximum solubility in that solvent(say water). until that concentration of borax reached, we add more borax and we called it saturated solution. after saturation if we add more borax that will precipitated out / falls out.