During the citric acid cycle, what happens to acetyl-coa?

Acetyl-CoA donates two carbon atoms which eventually releases as carbon dioxide at the end of Citric Acid Cycle or Kerb Cycle.

Explanation:

Acetyl coenzyme A converts to oxaloacetate which then enters into the kerbs cycle or citric Acid cycle.  

In the first stage of Citric Acid Cycle (CAC), the two carbon atoms of acetyl group i.e acetyl CoA combine with four carbon atom of oxaloacetate molecule and produce citrate which is a six carbon molecule. Thus, in general it can be said that each acetyl group contribute two carbon atoms in CAC and by the end of CAC these two carbon atoms are released as carbon dioxide.