##color(blue)(2″Al”(s) + 6″HCl”(aq) -> 3″H”_2(g) + 2″AlCl”_3(aq))##
This reaction is between a metal and an acid which typically results in a salt and the release of hydrogen gas. The unbalanced reaction is
##Al + HCl -> H_2 + AlCl_3##.
This is a redox reaction, whose half-reactions are and become:
##2(“Al”(s) -> “Al”^(3+)(aq) + cancel(3e^(-)))## ##3(2″H”^(+)(aq) + cancel(2e^(-)) -> “H”_2(g))## ##”———————————————–“## ##2″Al”(s) + 6″H”^(+)(aq) -> 3″H”_2(g) + 2″Al”^(3+)(aq)##
Aluminum oxidizes as ##”Al” -> “Al”^(3+)##, while hydrogen reduces as ##2″H”^(+) -> “H”_2^0##.
If we add back the spectator ##”Cl”^(-)##, we get:
##color(blue)(2″Al”(s) + 6″HCl”(aq) -> 3″H”_2(g) + 2″AlCl”_3(aq))##
I hope this was helpful.