Hi everyone,

 

So when sodium thiosulphate & hydrochloric acid react what is happening in terms of bonds breaking/being made to creat the new products?

 

1)In the word formula we write:

Sodium thiosulphate + hydrochloric acid → sulphur + sulphur dioxide +chloride which is fine but 2NaCl is Sodium Chloride is n't it? So why do we omitt the Sodium in the wording of the products and just call it chloride?

 

Also what happens to the hydrogen of the hydrochloric acid? It's part of the reactants but it isn't a product?

 

Na2S2O3(aq) + 2HCl(aq) → S(s) + SO2(g) + 2NaCl(aq)

 

2Na2S2O3(aq) + 4HCl(aq) → S(s) + 3SO2(g) + 4NaCl(aq)

 

But back to my original question - it is the acid that is responsible for breaking the sodium thiosulphate bonds and causing the products? But the hydrochloric acid is also broke - so does the sodium thiosulphate do this?

 

 

thanks for your help people!

You shouldn't omit the word "sodium" from "sodium chloride". After all, NaCl is sodium chloride, like you said.

 

Your equation is also incorrect; another product of the reaction is water.

ah ok, but there isn't enough oxygen on the reactants side to make 2H2O? unless we do this:

 

4Na2S2O3(aq) + 4HCl(aq) → S(s) + 3SO2(g) + 4NaCl(aq) + 2H2O

is this right? i think i am loosing my mind!

sorry please ignore the above post, you lot must think i am crazy!

 

hydrochloric acid + sodium thiosulphate= sodium chloride + sulphur dioxide + sulphur + water.

2HCl(aq) + Na2S2O3(aq) = 2NaCl(aq) + SO2(g) + S(s) + H2O

 

 

The above is balanced and correct isn't it? Back to my original question, it is the acid that is breaking everything up?

The above is correct, except that it is better to write ionic equations (in fact, HCl(aq) is non-existent, HCl does not simply dissolve in water, it reacts with water). Thiosulphate is the anion of the weak acid H2S2O3. This acid is very unstable, and slowly decomposes, giving H2O, SO2 and S.

 

A more accurate description of what happens is the following:

 

2H(+) + S2O3(2-) ---> H2S2O3 (this is a quick reaction)

 

H2S2O3 ---> S + SO2 + H2O (slower reaction, the solution turns turbid slowly)

 

The Na(+) ions and Cl(-) ions do not participate in the reaction, they are spectator ions.

and we can then go on to say that: SO2 + H2O = HSO3− + H+

 

sorry, I couldn`t resist