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Chemistry help a level

What is observed when concentrated hydrochloric acid is added to an aqueous
solution of CuSO4 until no further change occurs?
[1 mark]
A A colourless gas is evolved and a precipitate forms.
B A colourless gas is evolved and no precipitate forms.
C A precipitate forms that dissolves in an excess of
concentrated hydrochloric acid.
D The solution changes colour and no precipitate*forms
I know it's D but I need help on why. I do aqa chemistry a level. Is this q based off of the process of elimination or smth*on*the*spec
Im assuming its true that the Cu2+ is in its aqua ion form and is actually [Cu(h20)6]2+. i thought it would react with the cl- from the hcl and entropy and stuff makes the ligand substitution feasible turning it into [Cu(cl)4]2-. But i searched it up and it's just displacement and makes it CuCl2+H2SO4. But why is it this and not the transition metal complex*stuff???
or am i meant to know bcs for both eqns the only products are cucl2, h2so4 and*[Cu(Cl)4]2-.
so a gas wouldn't be formed, eliminating both*A*and*B
all of these are ions so a ppt wouldn't form, eliminating*C
Leaving D

so either process of elimination is what im meant to do. if so, then why is it not a complex thing created but just a simple displacement? and is this eqn on the spec bcs i haven't*seen*it*b4

thank you
Original post by AntonSlayer
What is observed when concentrated hydrochloric acid is added to an aqueous
solution of CuSO4 until no further change occurs?
[1 mark]
A A colourless gas is evolved and a precipitate forms.
B A colourless gas is evolved and no precipitate forms.
C A precipitate forms that dissolves in an excess of
concentrated hydrochloric acid.
D The solution changes colour and no precipitate*forms
I know it's D but I need help on why. I do aqa chemistry a level. Is this q based off of the process of elimination or smth*on*the*spec
Im assuming its true that the Cu2+ is in its aqua ion form and is actually [Cu(h20)6]2+. i thought it would react with the cl- from the hcl and entropy and stuff makes the ligand substitution feasible turning it into [Cu(cl)4]2-. But i searched it up and it's just displacement and makes it CuCl2+H2SO4. But why is it this and not the transition metal complex*stuff???
or am i meant to know bcs for both eqns the only products are cucl2, h2so4 and*[Cu(Cl)4]2-.
so a gas wouldn't be formed, eliminating both*A*and*B
all of these are ions so a ppt wouldn't form, eliminating*C
Leaving D
so either process of elimination is what im meant to do. if so, then why is it not a complex thing created but just a simple displacement? and is this eqn on the spec bcs i haven't*seen*it*b4
thank you
It does make [CuCl4]2- complex, a yellow solution.
https://edu.rsc.org/exhibition-chemistry/a-spectacular-reversible-reaction/2020036.article#:~:text=When%20concentrated%20hydrochloric%20acid%20is,of%20a%20copper%20chloride%20complex.
‘When copper sulfate dissolves in water, the water molecules act as ligands, producing the complex ion [Cu(H2 O)6]2+. When concentrated hydrochloric acid is added, ligand exchange occurs:
[Cu(H2O)6]2+ + 4Cl- [CuCl4]2- + 6H2O’
Reply 2
Original post by BankaiGintoki
It does make [CuCl4]2- complex, a yellow solution.
https://edu.rsc.org/exhibition-chemistry/a-spectacular-reversible-reaction/2020036.article#:~:text=When%20concentrated%20hydrochloric%20acid%20is,of%20a%20copper%20chloride%20complex.
‘When copper sulfate dissolves in water, the water molecules act as ligands, producing the complex ion [Cu(H2 O)6]2+. When concentrated hydrochloric acid is added, ligand exchange occurs:
[Cu(H2O)6]2+ + 4Cl- [CuCl4]2- + 6H2O’


Thanks, I spent hours looking at this and researching. I did come across this site but I discounted it because I saw the CuCl2 a first so I thought the complex stuff was wrong. Thank you. Also is my reasoning for deducing the answer correct? Or is there something else at play?
Original post by AntonSlayer
Thanks, I spent hours looking at this and researching. I did come across this site but I discounted it because I saw the CuCl2 a first so I thought the complex stuff was wrong. Thank you. Also is my reasoning for deducing the answer correct? Or is there something else at play?
Reasoning correct.

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