Why do some salts react with acids while others don't?

[nyrychvantel]

I am new to the concepts of reaction between of Acids, Bases and Salts.
While learning, I notice that some salts react with acids to form a new salt (and sometimes a new acid is produced), especially in Qualitative Analysis, while some don't even reacts.
I tried to search the internet about it but to no avail, I've no choice but to ask you guys.


Why is it that some salts do not react with acids? Is it because of it's solubility in water or other reasons?
That also contradicts me because CuCO_3 + H_{2}SO_4 \longrightarrow CuSO_4 + H_2O + CO_2
CuCO_3 is an insoluble salt, but it is still able to react with acids.


Why do salts even react with acids in the first place, that doesn't make sense to me.
For example if CaNO_{3} reacts with HCl to produce CaCl_2and HNO_3, why woundn't the CaCl_2 reacts with HNO_3 again to form back CaNO_{3} and HCl?

 

[GCT]

Acids favor the dissolution of salts via the La Chetelier's principle - this is one way.




For your second question consider which is the better acid.

 

[Kushal]

there are many acids, and each one has its own 'strength'. sulphuric acid is a stronger acid than ethanoic acid.

if you have ethanoic acid reaction with NaOH, you will get the salt sodium ethanoate. but if you then add sulphuric acid to this salt, the weaker ethanoic acid will be displaced by the stronger sulphuric acid to give sodium sulphate and ethanoic acid back.

HCl is stronger than HNO3 which is stronger than H2SO4...etc

HCl will be able to displace HNO3 from a nitrate salt, but HNO3 will not be able to displace the stronger HCl from a chloride salt.HCl will displace the weaker carbonic acid from the carbonate as well.