`Mg+2HCl->MgCl_2+H_2(a)`
`MgO+2HCl->MgCl_2+H_2O(b)`
`n_{Mg}=n_{H_2}=(2,24)/(22,4)=0,1mol`
`m_{Mg}=0,1.24=2,4g`
`n_{MgCl_2(a)}=n_{H_2}=0,1mol`
`m_{MgCl_2(a)}=0,1.(24+35,5.2)=9,5g`
`m_{MgCl_2(b)}=28,5-9,5=19g`
`n_{MgCl_2(b)}=(19)/(24+35,5.2)=0,2mol`
`n_{MgO}=n_{MgCl_2(b)}=0,2mol`
`m_{MgO}=0,2(24+16)=8g`
`a_{g(hh)}=2,4+8=10,4g`
`n_{HCl}=0,1.2+0,2.2=0,6mol`
`x_{M}=(0,6)/(0,4)=1,5M`