The balanced chemical equation for the reaction between oleic acid (C₁₈H₃₄O₂) and sodium hydroxide (NaOH) is:

C₁₈H₃₄O₂ (oleic acid) + 3NaOH (sodium hydroxide) → C₁₈H₃₃O₂Na (sodium oleate) + 3H₂O (water)

In this reaction, one molecule of oleic acid reacts with three molecules of sodium hydroxide to produce one molecule of sodium oleate and three molecules of water.