Gọi a là số mol Al
\(Al^0\left(a\right)\rightarrow Al^{3+}+3e\left(3a\right)\)
\(2N^{5+}+8e\left(0,12\right)\rightarrow N^{1+}_2\left(0,015\right)\)
\(N^{5+}+3e\left(0,03\right)\rightarrow N^{2+}\left(0,01\right)\)
Bảo toàn e \(\Rightarrow0,03+0,12=3a\)
\(\Rightarrow a=0,05\left(mol\right)\)
\(\Rightarrow m=1,35\left(g\right)\)