Acidic and Basic Salts (1 Viewer)

[High123]

I got a coupla questions
Is NaHSO4 an acidic or basic salt. Isn't bicarbonate ion amphiprotic? a

and also is CaCl2 acidic, basic or neutral.
By Bronsted Lowry theory of acid and bases, Ca is from weak base(CaOH) and Cl is from strong acid HCl so wouldn't it make a weak acid. Wikipedia says CaCl2 is neutral why is that?

A thanks in advance to all answerers. THANKS!!

 

[Hayzazz]

Ok first of all, you need to work out the acid and base that formed this salt.

For NaHSO4, H2SO4 is a strong acid, and NaOH is a strong base, and so the salt formed from these two, NaHSO4, is a neutral salt.

For CaCl2, it came from HCl, a strong acid, and Ca(OH)2, a strong base, and therefore the salt, CaCl2, will also be neutral.

 

[High123]

Nice, thanks for explaining but isn't NaHSO4 acidic with pH of 1.7 or something? It says so in conquering chem and I was wondering why. I get what your saying at that seems like the right answer to me but CC says otherwise.

 

[Freestyler94]

Ok first of all, you need to work out the acid and base that formed this salt.

For NaHSO4, H2SO4 is a strong acid, and NaOH is a strong base, and so the salt formed from these two, NaHSO4, is a neutral salt.

For CaCl2, it came from HCl, a strong acid, and Ca(OH)2, a strong base, and therefore the salt, CaCl2, will also be neutral.

Thats wrong, Sodium Bisulfate is an acidic salt, its because sulfuric acid is diprotic, So when it forms HSO4, HSO4 is a weak acid.

 

[fl0]

I use this table to figure it out (from Chemistry Contexts 2)

so for NaHSO4, break the salt into its ions, so we have the ion Na+ and HSO4-. Looking at the table, Na+ is neutral (this just means it doesn't react with water further and so doesn't want to become a base again), and HSO4- is acidic. So acidic ion + neutral ion = acidic ion.

And for CaCl2, Ca2+ is a neutral ion (doesn't react with water, doesn't want to become a base ) and Cl- is a neutral ion (doesn't react with water, doesnt want to become an acid again)as well. Meaning when both ions react with water, nothing happens meaning the CaCl2 is a neutral salt.

I hope this explanation helps. I found this quite hard at first.. but once you understand how the table works, memorise it and you will be fine for all problems related to acidic/basic salts.

 

[Hayzazz]

Thats wrong, Sodium Bisulfate is an acidic salt, its because sulfuric acid is diprotic, So when it forms HSO4, HSO4 is a weak acid.

Oh oops :S

So the HSO4 ion is slightly acidic, but because the sodium isnt basic nor acidic, the whole salt becomes acidic? Makes sense.

 

[Aindan]

Yeah this stuff was confusing for me at first. The best way to understand it is to write equilirbrium reactions with what the anion and cation of the salt will do and then decide whether this reaction can happen or not. for example ammonium chloride - NH4Cl.
NH4 + h20 <-> NH3 + h30, this reaction can occur and therefore some H+ ions will cause the solution to be acidic.
Cl + H20 <-> HCL + OH, this reaction could never occur because HCL is a strong acid and would ensure this reaction is so far to the left that no OH ions are made.
Therefore the salt NH4CL is acidic since it produces H+ ions.