\(n_{H_2}=\dfrac{3,36}{22,4}=0,15mol\)
Mg+2HCl\(\rightarrow\)MgCl2+H2
MgO+2HCl\(\rightarrow\)MgCl2+H2O
\(n_{Mg}=n_{H_2}=0,15mol\rightarrow m_{Mg}=0,15.24=3,6gam\)
\(m_{MgO}=11,6-3,6=8gam\rightarrow n_{MgO}=\dfrac{8}{40}=0,2mol\)
\(n_{MgCl_2}=n_{Mg}+n_{MgO}=0,15+0,2=0,35mol\)
\(m_{dd}=11,6+653,7-0,15.2=665gam\)
C%MgCl2=\(\dfrac{0,35.95.100}{665}=5\%\)