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

1 Answer

Answer:

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