How many moles of Fe ^ 2 + ions are formed when excess of iron...

$∵$ Reaction between $Fe$ and $HCl$ is as follows

$Fe + 2HCl ⟶ \mathop{FeCl2}_{( + 2 )} + {H}_{2}$ on reaction

$n$(moles of $Fe$) $= n$ (moles of $HCl$)

$n ( Fe ) =$ Normality $( HCl ) \times$ Volume of $HCl$

$n\left(Fe\right) = \dfrac{0. 4 \times 500}{1000} = 0. 2moles$

As each $Fe$ consumers $2$ electrons to change to ${Fe}^{2 +}$ ion.

$∴$ Number of ${Fe}^{2 +}$ ions produced $= \dfrac{0. 2}{2} = 0. 1mole$