Đáp án đúng: D
1
$\begin{array}{l}\text{2Fe}{{\text{S}}_{\text{2}}}\text{+}\frac{\text{11}}{\text{2}}{{\text{O}}_{\text{2}}}\xrightarrow{{{\text{t}}^{\text{o}}}}\text{F}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}\text{+4S}{{\text{O}}_{\text{2}}}\uparrow \\\,\,\,\,\text{x}\,\,\,\,\to \,\,\,\frac{\text{11x}}{\text{4}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\xrightarrow{{}}\,\,\,\,\,\,\,\,\,\,\,\text{2x}\\\text{2FeC}{{\text{O}}_{\text{3}}}\text{+}\frac{\text{1}}{\text{2}}{{\text{O}}_{\text{2}}}\xrightarrow{{{\text{t}}^{\text{o}}}}\text{F}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}\text{+2C}{{\text{O}}_{\text{2}}}\uparrow \\\,\,\,\,\,\text{x}\,\,\,\,\,\,\to \,\,\,\,\,\,\frac{\text{x}}{4}\,\,\,\,\,\,\,\,\,\,\,\,\,\xrightarrow{{}}\,\,\,\,\,\,\,\,\,\,\,\,\,\text{x}\end{array}$
$\begin{array}{l}\Rightarrow {{\text{n}}_{{{\text{O}}_{\text{2}}}\,\,\text{pu}}}\text{=}\frac{\text{11x}}{\text{4}}\text{+}\frac{\text{x}}{\text{4}}\text{=3x}\\{{\text{n}}_{\text{C}{{\text{O}}_{\text{2}}}}}\text{+}{{\text{n}}_{\text{S}{{\text{O}}_{\text{2}}}}}\text{=3x=}{{\text{n}}_{{{\text{O}}_{\text{2}}}\,\text{pu}}}\Rightarrow {{\text{n}}_{\uparrow \,\text{trc}}}\text{=}{{\text{n}}_{\uparrow \,\text{sau}}}\Rightarrow {{\text{P}}_{\text{1}}}\text{=}{{\text{P}}_{\text{2}}}\end{array}$
