  Self-organized criticality is characterized by power law correlations in the
non-equilibrium steady state of externally driven systems. A dynamical system
proposed here self-organizes itself to a critical state with no characteristic
size at ``dynamical equilibrium''. The system is a random solid in contact with
an aqueous solution and the dynamics is the chemical reaction of corrosion or
dissolution of the solid in the solution. The initial difference in chemical
potential at the solid-liquid interface provides the driving force. During time
evolution, the system undergoes two transitions, roughening and
anti-percolation. Finally, the system evolves to a dynamical equilibrium state
characterized by constant chemical potential and average cluster size. The
cluster size distribution exhibits power law at the final equilibrium state.
