`PTHH:` `Mg` `+` `2HCl` `->` `MgCl_2` + `H_2` `(1)`

            `Zn` `+` `2HCl` `->` `ZnCl_2` + `H_2` `(2)`

            `2Al` `+` `6HCl` `->` `2AlCl_3` + `3H_2` `(3)`

`Gọi:` `n_(Mg)` `=` `a` , `n_(Zn)` `=` `b`, `n_(Al)` `=` `c` `(a,b,c >0)`

`=>` `24a``+``65b``+``27c` `=` `35` `(I)`

`Từ` `phương` `trình` `1` `=>` `n_(H_2)` `=` `a`

`Từ` `phương` `trình` `2` `=>` `n_(H_2)` `=` `b`

`Từ` `phương` `trình` `3` `=>` `n_(H_2)` `=` `2/3c`

`Theo` `bài` `ra:`

`{(c=4/3a(II)),(n_(H_2)=(19,04)/(22,4)=17/20):}` 

`=>` `a+b+2/3c = 17/20 = 0,85` `(III)`

`Từ` `(I),(II),(III)` 

`=>` `{(a=0.15),(b= 0.4),(c=0.2):}`

=> `{(m_(Mg) = 3.6),(m_(Zn) = 26),(m_(Al) = 5.4):}`

`Hh:Mg:x(mol);Zn:y(mol);Al:z(mol)`

`24x+65y+27z=35(1)`

`Mg+2HCl->MgCl_2+H_2`

`Zn+2HCl->ZnCl_2+H_2`

`2Al+6HCl->2AlCl_3+3H_2`

Theo pt:

`n_{H_2}=x+y+1,5z={19,04}/{22,4}=0,85(2)`

`n_{H_2(Mg)}.2=n_{H_2(Al)}`

`->2x=1,5z(3)`

`(1)(2)(3)->x=0,15;y=0,4;z=0,2`

`m_{Mg}=0,15.24=3,6(g)`

`m_{Zn}=0,4.65=26(g)`

`m_{Al}=0,2.27=5,4(g)`