Question

What are the oxidation and reduction equations for when zinc is placed in HCl?

Answer 1

Zinc is oxidized to `Zn^(2+)`.........

Explanation:

`Zn(s) rarr Zn^(2+) + 2e^-` `(i)`

And hydronium ion is REDUCED to dihydrogen gas.........

`H_3O^+ + e^(-) rarr 1/2H_2(g) +H_2O(l)` `(ii)`

And we add the equations together to eliminate the electrons.....

`Zn(s) + 2H_3O^+ rarrZn^(2+) + H_2(g)uarr +2H_2O(l)`

And since chloride anion is conceived to be a spectator in this reaction.....

`Zn(s) + 2HCl(aq) rarrZnCl_2(aq) + H_2(g)uarr`

Is mass balanced? Is charge balanced? If the answer is NO, then the reaction cannot be considered to represent reality.