The problem of combined heat and mass transfer of a perfect conducting micropolar fluid in MHD natural convection adjacent to an infinite vertical surface is analyzed. The mass transfer equation includes the chemically reactive species of first order and the heat transfer equation includes the internal heat generation. A uniform magnetic field acts perpendicular to the plate. The state space technique developed in Ezzat [1] is adopted for the solution of one-dimensional problems for any set of boundary conditions. The resulting formulation together with the Laplace transform techniques are applied to a thermal-chemical reactive shock problem in a half space. The inversion of the Laplace transforms is carried out using a numerical approach. Numerical results for the temperature, concentration, velocity, microrotation and induced magnetic field distributions are given and illustrated graphically for the problem considered. (C) 2010 Elsevier Ltd. All rights reserved.