The onset of convective instability driven by thermodiffusion of nanoparticles and solute in reactive binary nanofluids is investigated theoretically using linear stability theory and addition factor analysis. A horizontal layer of reactive binary nanofluid at constant and different temperatures and concentrations is taken and the problem is modeled by the system of highly nonlinear partial differential equations. The stability equations are formulated and the expression for Rayleigh number is derived for stationary and oscillatory convections. The effect of nondimentional parameters namely chemical reaction parameter, volume fraction of nanoparticles, Soret coefficients, Prandtl number, heat of reaction parameter and addition factor on stability of the system is shown graphically. The water/ammonia based silver binary nanofluid is considered and the impact of nanoparticles on the stability is studied by employing the Brinkman model for viscosity and Bruggeman model for thermal conductivity. The enhancement of heat transport is analysed by calculating ratio of heat transfer coefficients.