In the paper the results of the experimental investigation of convective instabilities driven by an acid-base neutralization reaction are reported. Experiments were performed in a Hele-shaw cell. Aqueous solutions of nitric acid and alkali metal hydroxides (Li, Na, K) were used as reactants. Depending on the initial reactants concentration, two reaction modes are observed. The first one is a diffusion mode, where the predominant mass transfer mechanism is diffusion, leading to slow rates of reaction and the second one is convective regime characterizing by the formation of the intense convective motion and rapid reaction. Moreover a new type of instability was found (Fig.1). Physical model of the observed phenomenon and maps of regimes for various pairs ”acid - base” have been proposed.

The work was supported by the RFBR (project 16-31-00251 and

Keywords: Convection, Multiphase flows, Miscible fluids