H2C2O4 · H2O is the chemical formula for oxalic acid monohydrate. It's a solid, not a reaction.

If you're asking about the decomposition of oxalic acid monohydrate, it will break down into oxalic acid (H2C2O4) and water (H2O):

H2C2O4 · H2O → H2C2O4 + H2O

This process typically occurs upon heating.

Let me know if you were asking about a different reaction involving oxalic acid monohydrate!