The unsteady stagnation-point ow of a hybrid nanouid over a stretching/shrinking sheet embedded in a porous med- ium with mass transpiration and chemical reactions is considered. The momentum and mass transfer problems are combined to form a system of partial differential equations, which is converted into a set of ordinary differential equa- tions via similarity transformation. These ordinary differential equations are solved analytically to obtain the solution for velocity and concentration proles in exponential and hypergeometric forms, respectively. The concentration prole is obtained for four different cases namely constant wall concentration, uniform mass ux, general power law wall con- centration and general power law mass ux. The effect of different physical parameters such as Darcy number Da1 ð Þ, mass transpiration parameter V C ð Þ, stretching/shrinking parameter d ð Þ, chemical reaction parameter ð Þ and Schmidt number Sc ð Þ on velocity and concentration prole is examined. Results show that, the axial velocity will decreases as the shrinking sheet parameter increases, regardless of whether the suction or injection case is examined. The concen- tration decreases with an increase in the shrinking sheet parameter and the chemical reaction rate parameter.

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