\(n_{H_2SO_4}=0.3\cdot1=0.3\left(mol\right)\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(0.3.....0.3..............0.3...........0.3\)
\(m_{Fe}=0.3\cdot56=16.8\left(g\right)\)
\(V_{H_2}=0.3\cdot22.4=6.72\left(l\right)\)
\(C_{M_{FeSO_4}}=\dfrac{0.3}{0.3}=1\left(M\right)\)