Na2SO4 (1 Viewer)

[243_robbo]

another one

what is the parent acid of the salt Na2SO4? Is it HSO4- or H2SO4. Because i cant seem to balance the neutralsiation of HSO4- and NaOH.

i have an assesment tomorrow and i can't seem to write the neutralisation reactions, does anybody know them

this is what i think so far: if you take the parent of na2SO4 as sulfuric acid (H2SO4) then:

2NaOH + H2SO4 ---> Na2SO4 + 2H2O which balances

buti still think the parent acid of Na2SO4 should be HSO4- but the neutraisation reaction won't balance

ie- NaOH + HSO4- ---> Na2SO4 + H20 try balancing it you'll go round in circles

I am stuck what should i do?

 

[insert-username]

buti still think the parent acid of Na2SO4 should be HSO4- but the neutraisation reaction won't balance

ie- NaOH + HSO4- ---> Na2SO4 + H20 try balancing it you'll go round in circles

Why should it be HSO₄? If the reaction doesn't balance, odds on it probably doesn't happen.


I_F

 

[mitochondria]

Alrighty, have you come across the terms monoprotic, diprotic, triprotic, multiprotic... etc.?

One of the classification for acids is how many donor protons they have. Clearly, HCl (Hydrochloric Acid) is monoprotic (can donate one proton per molecule of HCl). Other examples of monorpotic acids are the halic acids - HF, HBr, BI (of course there are more).

How, it should be obvious to us that diprotic acids are those that have two donor protons. A typical example is H₂SO₄ (Sulfuric Acid).

In fact, you have suggested the typical diprotic acid-base reaction above:

2NaOH_(aq) + H₂SO_4(aq) -----> Na₂SO_4(aq) + H₂O_(l)

The parent acid of Na₂SO₄ is thus H₂SO₄.

If they are asking your for the parent acid for salts and you end up having a charge on your parent acid you are probably wrong. (For the scope of HSC...)

There is another reason why HSO₄^- does not qualify as a parent acid. HSO₄^- is what we call amphiprotic species and it can in fact act as both acid and base. The pH-dependent equilibrium of HSO₄^- is given by:


HSO₄^- + H⁺ -----> H₂SO₄

under acidic conditions; and


HSO₄^- + OH^- -----> SO₄^2- + H₂O

under basic conditions.

Everything here's HSC related Good luck!

 

[243_robbo]

cool thanks, with diprotic substances i thought they would have to give away protons in two step phases and not both at once as with this example, and thats why i still was thinking it might be hso4- but that kind of clears it up now

 

[mitochondria]

Well, as far as I know, experimentally the protons are not taken simultaneously. The second proton has a high pK_a value than the the first one; meaning that it is easier to deprotonate the first proton than the second proton.

However, with a strong base such as NaOH, you can assume that the second proton will also be deprotonated (provided that you have enough NaOH floting around)

Don't worry too much about this. In the meantime, just learn enough to kill the HSC but do come back if you really want to know more! Good luck!