\(\begin{array}{*{20}{l}}
{2Al + 6HCl \to 2AlC{l_3} + 3{H_2}}\\
{A{l_2}{O_3} + 6HCl \to 2AlC{l_3} + 3{H_2}O}\\
{a)}\\
{n{H_2} = \frac{{6,72}}{{22,4}} = 0,3{\mkern 1mu} mol}\\
{ = > nAl = 0,2{\mkern 1mu} mol}\\
{mAl = 0,2 \times 27 = 5,4g}\\
{mA{l_2}{O_3} = 27 - 5,4 = 21,6g}\\
{\% mAl = 20\% }\\
{\% mA{l_2}{O_3} = 80\% }\\
{b)}\\
{nHCl = 0,2 \times 3 + 0,21 \times 6 = 1,86{\mkern 1mu} mol}\\
{V{\rm{dd}}HCl = \frac{{1,86}}{2} = 0,93l}\\
{ = > m{\rm{dd}}HCl = 0,93 \times 1000 \times 1,12 = 1041,6g}\\
{c)}\\
{m{\rm{dd}}spu = 27 + 1041,6 - 0,3 \times 2 = 1068g}\\
{C\% AlC{l_3} = 7,75\% {\rm{\;}}}
\end{array}\)
