One of my students made a solutions, magnesium sulfate, potassium alum, and sodium citrate and forgot to label. While I'm mildly annoyed, the issue
is now is there a quick and easy way to figure out which is whichDraconicAcid - 17-2-2023 at 11:03
Add base. Sodium citrate will do nothing.
Magnesium sulphate will give a precipitate of Mg(OH)2
Potassium alum will give a gelatinous precipitate of Al(OH)3, which dissolves with excess hydroxide.Admagistr - 17-2-2023 at 17:36
One of my students made a solutions, magnesium sulfate, potassium alum, and sodium citrate and forgot to label. While I'm mildly annoyed, the issue
is now is there a quick and easy way to figure out which is which
It is exactly as DraconicAcid writes.Use alkaline hydroxide NaOH,KOH,do not use ammonia solution!Al(OH)3 will not dissolve
in excess NH4OH.Put samples in 3 tubes and add NaOH,or KOH solution drop by drop,Al(OH)3,or AlOOH will dissolve to NaAl(OH)4,or KAl(OH)4 in
excess NaOH,or KOH.
[Edited on 18-2-2023 by Admagistr]
[Edited on 18-2-2023 by Admagistr]unionised - 18-2-2023 at 10:24
Use pH paper.
The strongly acidic one is alum. The alkaline one is Sod. citrate and the near neutral one is Epsom salts.
