A general and local reactive boundary condition (RBC) for studying first‐order equilibrium reactions using the lattice Boltzmann method is presented. Its main characteristics are accurate reproduction of wall diffusion, invariance to the wall and grid orientation, and absence of nonphysical artifacts. The scheme is successfully tested for different benchmark cases considering diffusion, advection, and reactions of fluids at solid‐liquid interfaces. Unlike other comparable RBCs from the literature, the novel scheme is valid for a large
range of Péclet and Damköhler numbers, and shows realistic pattern formation during precipitation. In addition, quantitative results are in good accordance with analytical solutions and values from literature. Combining the
new RBC with the rest fraction method, Péclet‐Reynolds ratios of up to 1,000 can be achieved. Overall, the novel RBC accurately models first‐order reactions, is applicable for complex geometries, and allows efficiently
simulating dissolution and precipitation phenomena in fluids at the pore scale.