In this work, we present our calculations, based on density functional theory (DFT) to explore chemical reactivity of C2X (X = K-Br) towards CO molecule. Computed condensed Fukui function (f(-)) reveals the carbon atom of C2X (X = K-Br) to be the most active site for the CO interaction. This fact is also confirmed by the comparatively lesser average local ionization energy (I((r) over bar)) for the active carbon atom. Bader's topological parameters such as electron density rho > 0.30 a.u. with negative del(2)rho and H-BCP (total energy density) at the bond BCP of the carbon atoms of both C2X (X = K-Br) and CO infers the CO interaction in all the cases to be of shared-kind. (C) 2016 Elsevier B.V. All rights reserved.