Diffusion of a reagent from a slowly rising droplet with accompanying surface chemical reaction

Abstract

The development of neutralization reaction during the reagent diffusion from an insoluble drop, slowly floating up in a quiescent chemically active liquid, was studied experimentally. The droplet is located in a narrow vertical gap, which causes it to take the form of a short horizontal cylinder with a free lateral surface and flat end faces. The latter circumstance allows using an interferometer to visualize the structure of the fields of reagent concentration in the droplet and the resultant products in the environment and to trace their evolution. To display the specific features of the observed phenomena, we also investigated the diffusion of a reagent from a motionless drop in a chemically active medium and diffusion of a reagent from a drop floating up in a chemically neutral liquid.