How can I balance this chemical equations? Aluminum and hydrochloric acid react to form aluminum chloride and hydrogen gas.

1 Answer

color(blue)(2"Al"(s) + 6"HCl"(aq) -> 3"H"_2(g) + 2"AlCl"_3(aq))2Al(s)+6HCl(aq)3H2(g)+2AlCl3(aq)

Explanation:

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_3Al+HClH2+AlCl3.

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.