The reaction between sodium hydroxide (NaOH) and iron(II) sulfate (FeSO4) can be represented by the following chemical equation:

NaOH + FeSO4 → Fe(OH)2 + Na2SO4

In this reaction, sodium hydroxide acts as a base, while iron(II) sulfate acts as an acid. The reaction results in the formation of iron(II) hydroxide (Fe(OH)2) as a precipitate and sodium sulfate (Na2SO4) as a soluble salt.