\(n_{Fe}=\dfrac{6.72}{56}=0.12\left(mol\right)\)
\(n_{Cl_2}=\dfrac{3.36}{22.4}=0.15\left(mol\right)\)
\(2Fe+3Cl_2\underrightarrow{^{t^0}}2FeCl_3\)
\(0.1........0.15....0.1\)
\(m_{Fe\left(dư\right)}=\left(0.12-0.1\right)\cdot56=1.12\left(g\right)\)
\(m_{FeCl_3}=0.1\cdot162.5=16.25\left(g\right)\)