`a)`

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

`24x+65y=11,3(1)`

`2Mg+O_2` $\xrightarrow{t^o}$ `2MgO`

`2Zn+O_2` $\xrightarrow{t^o}$ `2ZnO`

`Mg+2HCl->MgCl_2+H_2`

`Zn+2HCl->ZnCl_2+H_2`

`MgO+2HCl->MgCl_2+H_2O`

`ZnO+2HCl->ZnCl_2+H_2O`

BTKL: `n_{O_2}={14,5-11,3}/{32}=0,1(mol)`

`->V=0,1.24,79=2,479(L)`

`n_{H_2}={2,24}/{22,4}=0,1(mol)`

Theo pt:

`x+y=2n_{O_2}+n_{H_2}=0,3(2)`

`(1)(2)->x=0,2;y=0,1`

`\%m_{Mg}={0,2.24}/{11,3}.100\%=42,48\%`

`\%m_{Zn}=100-42,48=57,52\%`

`b)`

Theo pt:

`n_{HCl}=4n_{O_2}+2n_{O_2}=0,6(mol)`

`m={0,6.36,5}/{20\%}=109,5(g)`

`n_{H_2O}=2n_{O_2}=0,2(mol)`

BTKL: `m'=14,5+0,6.36,5-0,1.2-0,2.18=32,6(g)`