a, Fe +2 HCl--> FeCl2 + H2
CuO + 2HCl--> CuCl2 + H2O
b, Ta có nH2=4/22,4=5/28 mol
=> nFe=nH2=5/28 mol
=> m Fe= 56.5/28=10 g
=> mCuO=mhhA - mFe=3,82 mol
c, %mFe=10.100/38,2=26,17%
%mCuO=100-26,17=73,83%
d, Ta có nCuO=3,82/80=0,04775 mol
Ta có nHCl=2(n Fe + nCuO)=6337/14000 mol
=> VddHCl=6337/(14000.2)=0,23M