[Rutherford]

In a solution of a chloride whose mass is 7.95g, Ag₂SO₄ is added. 23.55g of precipitate is made which is partially dissolved in ammonia. Write the formula of the chloride.
This seems though to me. I wrote the equation:
MCl+Ag2SO4 MSO4+AgCl
Can't balance it because I don't know if it is a mono-, di-... valent metal.
The precipitate is AgCl and MSO₄ together I think. Thought that M is Ba but didn't fit when I checked the equation and the masses. What to do?

[Borek]

Do you know any other insoluble sulfates?

Information given is enough to calculate equivalent mass of the element M, so there is no need for guessing.

[Rutherford]

How to use them if I can't balance the equation?

[Borek]

Start assuming it is M⁺ - balance the reaction equation and calculate molar mass of M. If no element fits, check if assuming it is M²⁺ doesn't help - and so on.

Note that you don't have to solve the problem separately each time, if you calculate molar mass assuming it is M⁺, molar mass of M²⁺ is just twice larger, that's how equivalents work.

[Rutherford]

Done how you said and I got SrCl₂. How can I assume that the molar mass is 2 times larger?

[Borek]

Do you know what a chemical equivalent is?

[Rutherford]

Found out what it is, but how to use it here? I found some simple problems but don't know how to use it here.

[Rutherford]

I think I understood now, correct me if I am wrong. First I assume that it is a monovalent metal (it can react with 1 mole of H so I will calculate its equivalent mass). Then I balance the equation and the mass I get is the equivalent mass. Got 44g/mol but there isn't any metal with that mass. If I assume that it is a divalent metal (it can react with 2 moles of H), then the equivalent mass would be 2 times higher. Is it so?

[Borek]

Yes.

[Rutherford]

Ok, thanks.

[AWK]

In this case both sulfates of (Pb, Ba, Ca or Sr) and AgCl (which is soluble in amonia) are insoluble!