How to determine the equation for the reaction of europium with sulfuric acid based on experimental measurements?
Your equation isn't balanced; the oxidation state for europium is +3 and not +1; and europium sulfate does not exist in the solution you describe.
From this link:

Reaction of europium with acids
Europium metal dissolves readily in dilute sulphuric acid to form solutions containing the very pale pink aquated Eu(III) ion together with hydrogen gas, $\ce{H2}$. It is quite likely that $\ce{Eu^3+}$(aq) exists as largely the complex ion $\ce{[Eu(OH2)9]^3+}$

$$\ce{2Eu(s) + 3H2SO4(aq) -&gt; 2Eu^{3+}(aq) + 3SO4^{2-}(aq) + 3H2(g)}$$