In this paper, the authors have made an attempt to investigate the influence of heat sink and first order chemical reaction on an MHD unsteady heat and mass transfer convective flow past an infinite vertical porous plate with variable suction, when the frequencies of oscillation of the plate temperature and the variable suction velocity are equal. Using regular perturbation scheme, analytical solutions have been derived for the equations governing the flow, heat and mass transfer. The expressions for the velocity, temperature, and the species concentration fields, and skin friction, Nusselt number and Sherwood number at the wall are derived and their natures are shown pictorially. The effects of the Schmidt number Sc, Prandtl number Pr, Soret number Sr, Hartmann number M, chemical reaction parameter Rand heat sink parameter Qon the flow, heat and mass transfer are analysed and interpreted.

When heat sink and chemical reaction are omitted, it is observed that the results in the present work are in agreement with those of Reddy et al. [13].

MHD flow, Schmidt number, viscous dissipation, chemical reaction, heat sink, skin friction.