在Fe2O3+3CO2Fe+2CO2的反应中,铁元素由+3价变为0价,碳元素由+2价变为+4

Fe2O3+3CO2Fe+2CO2反应中,铁元素由+3价变为0价,碳元素由+2价变为+4价。像这类凡有元素化合价升降的反应都属于氧化一还原反应。据此判断下列反应属氧化一还原反应的是( 

2Mg+O22MgO     2F2+2H2O4HF+O2  

CaCO3CaO+CO2

2KClO32KCl+3O2      2NaOH+SO2Na2SO3+H2O

A①②③       B②③④       C①②④       D③⑤

答案

C

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