All the reactions are correct , so what could be the appropriate answer then?

In which reaction is dilute sulfuric acid not behaving as an acid?
a) H2SO4 + 2NaOH = Na2SO4 +2H2O
b) H2SO4 + BaCl2 = BaSO4 + 2HCl
c) H2SO4 + CuO = CuSO4 + H2O
d) H2SO4 + Mg = MgSO4 + H2
* Pardon any tying error in the equations!

2 Answers
Jun 28, 2018

Is it not BB?

Explanation:

The net ionic equation is simply..

Ba^(2+) + SO_4^(2-) rarr BaSO_4(s)darrBa2++SO24BaSO4(s)...

The hydronium ion REMAINS in solution, i.e. "2 equiv"2 equiv H_3O^+H3O+...

Just in response to a request for clarification...I will try to make what I have written less confusing... We often speak of acidity in terms of the characteristic cation of the solvent...for water we often write...

H_2O(l)rightleftharpoonsH^+ + HO^-H2O(l)H++HO...and K_w=[HO^-][H^+]=10^-14Kw=[HO][H+]=1014.

Here, H^+H+ is CONCEIVED to be the acid principle...and HO^-HO is the base principle, the characteristic anion... An acid dissolved in water is INCREASES the concentration of the anion, i.e. for gaseous HClHCl we write...

HCl(g) stackrel(H_2O)rarrH_3O^+ + Cl^-HCl(g)H2OH3O++Cl

A saturated solution solution of HCl(aq)HCl(aq) is approx 10.6*mol*L^-110.6molL1 with respect to H_3O^+H3O+...

And of course the H^+H+ is a label of convenience..in aqueous solution what we term H^+H+ is possibly H_7O_3^+H7O+3 or H_9O_4^+H9O+4...i.e. a CLUSTER of 2-323 or more water molecules WITH AN EXTRA H^+H+ associated with the cluster. Certainly the H^+H+ can move rapidly from cluster to cluster, tunnel if you like, given the vast aqueous mobility of H^+H+ and HO^-HO...

And so we represent the acidium ion as H^+H+ or even H_3O^+H3O+...this is a CONCEPTION rather than the reality...but it is useful to write chemical equations invoking them as actual species... I have written much the same thing here and [here.](https://socratic.org/questions/586bb384b72cff43cf5b0319)

Anyway, I know that "Inorganic Chemistry, Principles of"Inorganic Chemistry, Principles of "Structure and Reactivity, J. E. Huheey"Structure and Reactivity, J. E. Huheey is available in most university libraries (it may even be available for download but you might have to pledge your first-born to get it), and this has a good chapter on the concept of acidity...good luck...

Jun 29, 2018

The correct answer is option b).

Explanation:

A substance behaves as an acid if it provides "H"^"+"H+ ions that get used up during a reaction.

It is easiest to see what is happening if we use net ionic equations.

a)

Molecular equation:
"H"_2"SO"_4"(aq)" + "2NaOH(aq)" → "Na"_2"SO"_4"(aq)" + 2"H"_2"O(l)"H2SO4(aq)+2NaOH(aq)Na2SO4(aq)+2H2O(l)

Ionic equation:
2"H"^"+""(aq)" + color(red)(cancel(color(black)("SO"_4^"2-""(aq)"))) + color(red)(cancel(color(black)("2Na"^"+""(aq)"))) +2"OH"^"-""(aq)" → color(red)(cancel(color(black)("2Na"^"+""(aq)"))) + color(red)(cancel(color(black)("SO"_4^"2-""(aq)"))) + 2"H"_2"O(l)"

Net ionic equation:
color(red)(cancel(color(black)(2)))"H"^"+""(aq)" +color(red)(cancel(color(black)(2)))"OH"^"-""(aq)" → color(red)(cancel(color(black)(2)))"H"_2"O(l)"

"H"^"+""(aq)" +"OH"^"-""(aq)" → "H"_2"O(l)"

"H"^"+" is getting used up in this reaction, so the sulfuric acid is behaving as an acid.

b)

Molecular equation:
"H"_2"SO"_4"(aq)" + "BaCl"_2"(aq)" → "BaSO"_4"(s)" + 2"HCl""(aq)"

Ionic equation:
color(red)(cancel(color(black)(2"H"^"+""(aq)"))) + "SO"_4^"2-""(aq)" + "Ba"^"2+""(aq)" + color(red)(cancel(color(black)("2Cl"^"-""(aq)"))) → "BaSO"_4"(s)" + color(red)(cancel(color(black)(2"H"^"+""(aq)"))) + color(red)(cancel(color(black)("2Cl"^"-""(aq)")))

Net ionic equation:
"SO"_4^"2-""(aq)" + "Ba"^"2+""(aq)" → "BaSO"_4"(s)"

"H"^"+" is a spectator ion.

It is not getting used up in this reaction, so the sulfuric acid is not behaving as an acid.

c)

Molecular equation:
"H"_2"SO"_4"(aq)" + "CuO(s)" → "CuSO"_4"(aq)" + "H"_2"O(l)"

Ionic equation:
2"H"^"+""(aq)" + color(red)(cancel(color(black)("SO"_4^"2-""(aq)"))) + "CuO(s)" → "Cu"^"2+""(aq)" + color(red)(cancel(color(black)("SO"_4^"2-""(aq)"))) + "H"_2"O(l)"

Net ionic equation:
2"H"^"+""(aq)" + "CuO(s)" → "Cu"^"2+""(aq)" + "H"_2"O(l)"

"H"^"+" is getting used up in this reaction, so the sulfuric acid is behaving as an acid.

d)

Molecular equation:
"H"_2"SO"_4"(aq)" + "Mg(s)" → "MgSO"_4"(aq)" + "H"_2"(g)"

Ionic equation:
2"H"^"+""(aq)" + color(red)(cancel(color(black)("SO"_4^"2-""(aq)"))) + "Mg(s)" → "Mg"^"2+""(aq)" + color(red)(cancel(color(black)("SO"_4^"2-""(aq)"))) + "H"_2"(g)"

Net ionic equation:
2"H"^"+""(aq)" + "Mg(s)" → "Mg"^"2+""(aq)" + "H"_2"(g)"

"H"^"+" is getting used up in this reaction, so the sulfuric acid is behaving as an acid.