Chemistry Question - Which Tests as an Acid Solution?

[oceanflavored]

[SOLVED] chemistry question.

Homework Statement

i'm studying for satII chem & got stuck on this problem. any help would be greatlyyy appreciated.
Which of the following when placed in water will test as an acid solution?
I. HCl (g) + H2O
II. Excess H3O+ + H2O
III. CuSO4 (s) + H2O

(A) I only
(B) II only
(C) I and II only
(D) II and III only
(E) I, II, and III

Homework Equations

don't think you really need anyyyy.
but the book says the answer is (E).

The Attempt at a Solution

well; I'm totally confused by this problem.
but i know (I) has to be true because HCl = strong acid. but as for the other ones, I'm very lost and would totally appreciate any help at alll.

thanks in advance! :)

 

[rocomath]

$$H_3O^+$$ is also $$H^+$$

III. what is the Product? Is either one of the products an acid?

$$CuSO_4 (s) + H_2O (l) \rightarrow ?$$

 

[oceanflavored]

thanks!

ok..thank you so much about the H3O

and as for the CuSO4 (s) + H2O

that's all the book says, there's no product.
their explanation is that the CuSO4 gives off an acid solution when it hydrolyzes in water.
but, i was confused as to how you would know that!

i hope that helps, rocophysics.
and thank you so much for your help!

 

[rocomath]

Even though they don't give you Products, choice III is saying that Copper sulfate and Water react; though it does not explicitly tell you what those Products are.

Reaction III is a Double displacement rxn so

$$CuSO_4 (s) + H_2O (l) \rightarrow CuO (s) + H_2SO_4 (aq)$$

 

[oceanflavored]

rocophysics, you are amazing!
thank you SO much!