State the formula of an ion found in both dilute propanoic acid in dilute hydrochloride acid ?

From the balanced chemical reaction, we can see that for every 4 moles of Fe (iron) formed, the heat released or heat of reaction is 1.65 x 10^3 kJ.

So calculate the moles of iron first:

moles iron = 250 g / (55.85 g/mol) = 4.48 mol

So the heat of reaction is:

δhrxn = (-1.65 x 10^3 kJ / 4 mol) * (4.48 mol) = -1.85 kJ