Hey guys! I am pretty confused about the salts and their acidity.
I would like to clarify my doubts as they appear frequently on the past papers.
I would like to know whether NaH2PO4 and NaHSO4 are acidic or basic or neutral?
Before I thought that NaH2PO4 would be basic because it is the salt made from NaOH strong base and H3PO4 weak acid. But when I searched google, they say it will be an acidic salt because the compound can still donate two H+ ions, and the same goes for NaHSO4.
So will this rule apply to all the other similar compounds as well? If the compound can still have H+ ions to donate, will we be able to consider it acidic? Can someone please explain these kindly? Thanks in advance
I also have troubles with these types of salts. In my opinion, NaHSO4 should be neutral because as it dissociates to form Na+ and HSO4-, the H+ ion can be both given off or accepted by the anion. So if anyone knows more about this topic, please enlighten us!
Hey! Yes, I used to think the same way but when I search on google, they say, it is slightly acidic cuz it can donate one H+ ions, I would like to clarify these too
This is how i interpret questions regarding salt and it’s hydrolysis hope it will be useful:
We can know that a salt is acidic or basic by checking its acidic and basic radicals , that is, it’s cation and anion.
We know that every salt is prepared from an acid and a base:
1). If a salt is prepared from a strong acid and a weak base it is acidic.
2).If a salt is prepared from a weak acid and strong base it is basic.
3).If a salt is prepared from a strong acid and a strong base it is neutral.
In order to find the Source Acid and base: The anion is basic radical. Add H+ to the anion of the salt. And cation is the acidic radical. Add OH- to the cation of the salt.
Let’s assume NaHso4 it dissociates to form Na+ and Hso4- so, in order to find the source acid and base add H+ to Hso4- and oH- to Na+ so the acid source is H2So4(2H+ and 1So42-) while the basic source is NaOH(Na+ and OH-) at first instance it seems like it’s a basic salt as it’s formed of a strong acid and a strong base but when you zoom in the constituents for every 1OH- ion we have 2H+ ions present so, even on neutralization we have a residual H+ ion left making the solution acidic.
Let’s take one more example to make things bit more clear let’s assume we have Na2Co3 on dissolution it breaks into 2Na+ and Co3 2- finding the acidic and basic source like previous example we have basic source as 2NaOH(2Na+ + 2OH-) and the acidic source is HCo3 well this one is pretty straight forward NaoH being strong base while HCO3 being weak acid together forms a basic salt.
We can use the same process for different salts the main problem arises when we have both strong base and strong acid there having a count of H+ and OH- turns useful the ones comprising of a strong component and the other weak are pretty easy to identify.
Hope it helps to a extent:)
Kindly share more on this topic to make it crystal clear.
Thank you so much @Ujjwal ! This is very helpful for me
Can you explain a bit more about the acidic and basic radicals, because according to ths explanation I think the cation would be the basic radical as we will add OH- to it.
The Anion is the basic radicle what i mean by it is as we know Anions have negative charged over them so they basically can accept a proton to form the acidic source just like in the eg. of NaHSo4 it dissociates into Na+ and Hso4- where Hso4- being the anion and it will accept the proton (H+) giving H2So4 which is the acidic source of this particular salt the same is true for Cations they accept OH- in place of H+.
Hope it make sense:)
Amazing explanation Ujjwal, thank you so much!