2H++Mg=H2+Mg2+
6H++2Al=3H2+2Al3+
列方程 设镁的摩尔数为n,铝为m,
24n+27m=10.2 n+1.5m=11.2/22.4
解n,m就行了,n=m=0.2mol,质量为4.8g和5.4g.