[greentalk2012]

In the first part of synthesis of Aspirin there was a base catalysed(NaOh) hydrolysis of 2 hydroxybenzoic acid and disodium salt formed,after addition of H2So4 crude product of salicylic acid precipitated,so, it precipitated because salicylic acid has lower solubility in water than disodium salt but how and why H+ outcompeted Na+?
Thanks

[Hunter2]

It is because sulfuric acid is a strong acid and salicylic acid is a weak one. The strong one cast out the weak one from there salt.