a)\(Fe+2HCl-->FeCl2+H2\)
\(n_{H2}=\frac{6,72}{22,4}=0,3\left(mol\right)\)
\(n_{Fe}=n_{H2}=0,3\left(mol\right)\)
\(m=m_{Fe}=0,3.56=16,8\left(g\right)\)
b)\(n_{HCl}=2n_{H2}=0,6\left(mol\right)\)
\(V_{HCl}=\frac{0,6}{2}=0,3\left(l\right)\)
c)\(n_{FeCl2}=n_{H2}=0,3\left(mol\right)\)
\(C_{M\left(FeCl2\right)}=\frac{0,3}{0,3}=1\left(M\right)\)