Dark energy hypothesis aims to explain the accelerated expansion of universe as indicated by evidence from Type Ia supernovae (SN 1a), Cosmic microwave background (CMB) and Baryon acoustic oscillations (BAO) data. Various models have been formulated to explain accelerated
expansion. In this paper, we review the Quintessence and Barotropic fluid models. We will discuss various parameters that can be used to distinguish these models in w-w' plane, where w is dark energy equation of state (EOS) and w' is the derivative of w with respect to the logarithm of scale factor. We will also analyze the behavior of w'', that is the second derivative of w with respect to logarithm of scale fact, for phantom and non-phantom region.