Question

The aqueous solution of aluminium-permanganete can be made with the combination ofaluminium-sulphate and potassium-permanganate solutions. We can get a pure aluminium-permanganete solution by the fact that potassium-aluminium-sulphate is practically insoluable in water at 0°C.

In what ratio should we combine the two saturated solutions at 80°C to get a pure solution of aluminium-permanganate?

Soluability at 80°C: 

Potassium permanganate: 33.7g/100g water

potassium-aluminium sulphate: 73.1g/100g water