What Is The Structural Formula Of Acetic Acid, Benzaldehyde And Formalin? What Is The Condense Formula Of Acetic Acid, Benzoic Acid And Phenol?

1) CH3C=O
  |
  OH
2) [Benzene ring] -C=O
  H
3) Formalin is a saturated solution of formaldehyde, water, and typically another agent, most commonly methanol

Condensed or empirical I think you mean are for 1 & 2 ,..
C2O2H4 and C7H6O