This paper demonstrates the use of the new lyer/Pickering/Zamanzadeh/Al-Faqeer (IPZA) analysis to determine the effect of the iodide surface coverage (theta(I)-) on the hydrogen surface coverage (theta(H)) and the rate constants of the hydrogen evolution reaction (HER) and hydrogen absorption reaction (HAR). Iodide ions have an inhibiting effect on the HER but they enhance the HAR. The IPZA analysis was used to determine theta(I)- in addition to the usual parameters: hydrogen discharge (k(i)) and recombination (k(2)) rate constants, hydrogen kinetic-diffusion constant (k) and theta(H). Inclusion of the iodide coverage is important as shown by a comparison with literature values that were obtained using the original IPZ analysis, which does not include the theta(I)- parameter. The theta(I)- values from the IPZA analysis were within reasonable agreement with theta(I)- values measured using the electrochemical quartz crystal microbalance (EQCM) and theta(I)- values calculated from the measured corrosion current densities before and after adding iodide to the electrolyte. (C) 2003 Elsevier Science Ltd. All rights reserved.