Đáp án đúng: D 6,72. $\begin{array}{l}\text{Fe+}{{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}\xrightarrow{{}}\text{FeS}{{\text{O}}_{\text{4}}}\text{+}{{\text{H}}_{\text{2}}}\\{{\text{n}}_{{{\text{H}}_{\text{2}}}}}\text{=}{{\text{n}}_{\text{Fe}}}\text{=}\frac{\text{16,8}}{\text{56}}\text{=0,3}\,\text{mol}\Rightarrow \text{V=6,72}\,\text{lit}\end{array}$
