\(n_{Fe}=\dfrac{1,68}{56}=0,03\left(mol\right)\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ 0,03....0,06.....0,03.......0,03\left(mol\right)\\ a,V_{H_2\left(đktc\right)}=0,03.22,4=0,672\left(l\right)\\ b,m_{HCl}=0,06.36,5=2,19\left(g\right)\\ c,m_{FeCl_2}=127.0,03=3,81\left(g\right)\)