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how to make alum sulphate solution from powder alum sulphate ? Answered

4 Replies

Toga_Dan (author)2017-07-07

Alum/ˈælum/ is both a specificchemical compound and a class of chemical compounds. The specific compound is the hydratedpotassiumaluminiumsulfate (potassium alum) with the formulaKAl(SO

. More widely, alums are double sulfate salts, with the general formula AM(SO
2O, where A is a monovalent cation such as potassium or ammonium and M is atrivalent metal ion such as aluminium orchromium(III).[1] When the trivalent ion is aluminium, the alum is named after the monovalent ion.

Lifted from wiki.

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rickharris (author)2017-07-04

Can you dissolve it in water?

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Jack A Lopez (author)2017-06-28

Well, I think the tricky parts to this question are twofold.

First is that I do not know what compound your powder is. Is it an alum?


Or is it aluminum sulfate?


Maybe we are abbreviating aluminum as alum? Why? Because OMG, spelling out words completely, is hard.


The second tricky part is these compounds often come, in the bottle, as some kind of hydrate; i.e. there is are already water molecules in the crystal structure, even if the powder appears to be bone dry.

In fact, for aluminum sulfate in particular, its common hydrated forms have huge amounts of water!

Aluminium sulfate is rarely, if ever, encountered as the anhydrous salt. It forms a number of different hydrates, of which the hexadecahydrate Al2(SO4)3•16H2O and octadecahydrate Al2(SO4)3•18H2O are the most common.

By the way, I have this free app, running under Ubuntu, that does molecular weight (mass) calculations,


and that ap is going to come in handy for telling me how much water those particular hydrates contain.

Al2(SO4)3 masses 342.15 g/mol

(H2O)16 masses 288.24 g/mol

(H2O)18 masses 324.28 g/mol

So the 16-water hydrate is about 46% water by mass, and the 18-water hydrate is about 49% water by mass.

Like I said, there are huuuuuuuuge amounts of water in those aluminum sulfate crystals!

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Downunder35m (author)2017-06-28

Try Google or Wikipedia with water....

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