[scamp]

hi
wondering if somebody could help explain to me how does the reaction of nacl + H3PO4 form nah2po4 and hcl gas?  i thought h3po4 was a weaker acid than hcl, so how can it form a stronger acid?
and does it depend on the strength of h3po4 used?

Thanks 

[FeLiXe]

with every chemical reaction you have an equlibrium

if you use phosphoric acid at a high concentration, then a little bit of HCl will form in spite of the fact that it is a stronger acid

if you heat the solution up you may be able to get HCl gas out of it

[Borek]

I suppose rection takes place with solid NaCl and concentrated H₃PO₄. Write the reaction equation, don't forget about (a), (g) & (s) indices.

[scamp]

so would you say that a reaction with solid nacl and concentrated h3po4 will react to form hcl gas, as the concentrated acid is strong enough to loose a h+,
if you tried to do the reaction with dilute h3po4 say 4M the reaction would not proceed?

thanks

[Borek]

Write reaction equation. Start paying attention to the capital letters in formulae.