Solving H2SO4 + NH4OH Acid-Base Reaction

[Mozart]

I have to write the complete ionic equation, list the spectator ions, and write the net ionic equation for H_2SO_4(aq) + NH_4OH(aq)

I thought I should attempt to write out the balanced chemical equation so this is what I got.

H_2SO_4(aq) + 2NH_4OH(aq) \longrightarrow SO_4(NH_4)_2(aq) + 2H_2O(l)


I just don't feel right about putting (NH_4)_2(aq) with SO_4(aq) I don't know why...

I won't bother writing out what I got for the complete ionic equation, spectator ions, and net ionic equation since it would all be wrong if my balanced chemical reaction was wrong.

Can someone please help me with this first step though. Many many thanks.

 

[PPonte]

I think the reaction should be:

H_2SO_4(aq) + 2NH_4OH(aq) \longrightarrow (NH_4)_2SO_4(aq) + 2H_2O(l)

Because,


H_2SO_4(aq) + 2NH_4OH(aq) \longrightarrow H^+ + SO_4^{2-} + NH_4^+ + OH^-

H^+ reacts with OH^- to form water.
NH_4^+ reacts with SO_4^{2-} to form (NH_4)_2SO_4, first the cation, then the anion and to have no charge they have to combine 2:1.

 

[mrjeffy321]

Sulfuric Acid (H2SO4) is a strong acid, Ammonium Hydroxide (NH4OH) is a weak base, together, they should produce a salt + water.
The salt they would produce would be Ammonium Sulfate [(NH4)2SO4].

H2SO4 (aq) + 2 NH4OH (aq) --> (NH4)2SO4 (aq) + H2O (l)

http://www.jtbaker.com/msds/englishhtml/A6192.htm" is soluble in water (41.22 g/100 mL), so it will be in solution in the final product.

Since both the Ammonium ad Sulfate ions are in solution in the reactants and products, in the net ionic equation, they cancel out, leaving just,
H+ (aq) + OH- (aq) --> H2O (l)

 

[ksinclair13]

I thought ammonium hydroxide was a strong base. For any strong acid-strong base reaction, the net ionic equation will be H⁺ + OH^- ---> H₂O

 

[mrjeffy321]

No, Ammonium Hydroxide is a weak base...weak as in it does not completely disassociate when dissolved, unlike H2SO4.

So, actually, I would like to revise my answer.
Since most of the NH4OH is not broken into ions, the net ionic reaction would be,
H+(aq) + NH4OH(aq) --> H2O(l) + NH4+(aq)
The H+ ion from the sulfuric acid will react with the NH4OH to make H2O and leave the Ammonium ion in solution.

 

[ksinclair13]

H₂SO₄ is a strong acid, but HSO₄^- is a very weak acid...so won't the H₂SO₄ dissociate into H⁺ and HSO₄^- ions and not completely into H⁺ and SO₄^2- ions?

Maybe I'm way off on this...

 

[Borek]

H₂SO₄ is a strong acid, but HSO₄^- is a very weak acid...so won't the H₂SO₄ dissociate into H⁺ and HSO₄^- ions and not completely into H⁺ and SO₄^2- ions?

Maybe I'm way off on this...

Slightly

HSO₄^- is weaker, but not as weak as you think. pKa2=2.

0.01M sulfuric acid has pH of 1.85. For a very weak second step you may expect pH=2.00.Borek