The onset of Ihermo-soluial convcclion In a fluid-saturated porous layer is studied when the chemirul equilibrium on the bounding surfaces and the solubility of the dissolved components depend on temperature. Sinusoidal vertical vibrations to the system are assumed to affect a time-dependent gravitational field for the onset of natural convection. A linear stability analysis Is performed to obtain the Rayleigh number as a function of system parameters. The effect of chemical reaction parameter (Damkohler number) on Rayleigh number is depicted graphically and Is discussed In detail. © 2015 Scientific Publishers. All Rights Reserved.