# What happens if you put a piece of copper into a solution containing Al3+ ions?

This is a question in my studies, and I am a little bit confused! I would think it happens nothing because copper is below aluminium in the reactivity series, right?

• You think right. – Ivan Neretin Apr 28 at 10:37
• As a side reaction, it may get slowly oxidized by oxygen and dissolve in acidic solution. – Poutnik Apr 28 at 11:08

You are right with copper does not react with aluminium ions.

But as a side reaction, copper may get slowly oxidized by oxygen and dissolve in mildly acidic solution of aluminium salt.

Such a thing may happen, if you decalcify copper heating spiral by vinegar and let it stay overnight.

$$\ce{ 2 Cu + 4 CH3COOH + O2 -> 2 (CH3COO)2Cu + 2H2O }$$

Something similar can happen in aluminium salt solutions as well, because of hydrolysis.

\begin{align} \ce{ [Al(H2O)6]^3+ + H2O &<=> [Al(H2O)5(OH)]^2+ + H+} \\ \ce{ 2 Cu + O2 + 4 H+ &-> 2 Cu^2+ + 2 H2O} \\ \ce{ 2 Cu + O2 + 2 H2O &-> 2 Cu(OH)2 v} \\ \ce{ 2 Cu + O2 + H2O + CO2 &-> Cu(OH)2\cdot CuCO3 v} \\ \end{align}

• Your first equation got me into chemistry more than two decades ago as a home experiment! Nostalgic. Copper is not supposed to dissolve in acetic acid, however a small amount H2O2 starts to dissolve it. – M. Farooq Apr 28 at 15:34
• I started when the chemistry textbook for a basic school, belonging to my 2-year-older sister, got into my hands. I do not remember any more interesting textbook ever :-) . – Poutnik Apr 28 at 15:38
• No, it was Czech one. I hardly ever knew few English words. English language was rather not preferred in the communist school system :-). German was taught more often because of the communist Eastern Germany – Poutnik Apr 28 at 15:42
• Eastern Europe was a leader in electrochemistry and theoretical side of chemistry. No wonder your electrochemistry is quite good. – M. Farooq Apr 28 at 15:45
• The Germany leader Dagmar Merkel is from Eastern Germany, doing post doc studies in quantum physics/chemistry in Prague at prof. Zahradník, the leader in Quantum chemistry development, later the head of the Czech academy – Poutnik Apr 28 at 15:50