Which of the following is an oxidation-reduction reaction?
Fe2O3 + 3CO mc009-1.jpg 2Fe + 3CO2
CuSO4 + 2NaOH mc009-2.jpg Cu(OH)2 + Na2SO4
2NaOH + H2CO3 mc009-3.jpg Na2CO3 + 2NaOH
Pb(NO3)2 + Na2SO4 mc009-4.jpg 2NaNO3 + PbSO4
Fe2O3 + 3CO mc009-1.jpg 2Fe + 3CO2
CuSO4 + 2NaOH mc009-2.jpg Cu(OH)2 + Na2SO4
2NaOH + H2CO3 mc009-3.jpg Na2CO3 + 2NaOH
Pb(NO3)2 + Na2SO4 mc009-4.jpg 2NaNO3 + PbSO4