ORIGINAL PAPER Scavenging Effects of Aliphatic Alcohols and Acetone on H • Radicals in Anodic Contact Glow Discharge Electrolysis: Determination of the Primary Yield of H • Radicals Urvashi Gangal • Monika Srivastava • Susanta K. Sen Gupta Received: 14 July 2009 / Accepted: 6 January 2010 / Published online: 5 February 2010 Ó Springer Science+Business Media, LLC 2010 Abstract A study of scavenging effects of iso-propanol, n-propanol, n-butanol and acetone on H • radicals, precursors for nonfaradaic products of anodic contact glow dis- charge electrolysis (CGDE) in aqueous media, has been carried out. A kinetic analysis of the competing reactions of H • with different species in the system leads to a primary yield of 9.8 mol (mol electron) -1 each of H • and OH • radicals in the liquid-phase reaction zone of anodic CGDE. The method is considerably more convenient to apply than those reported earlier based on the use of OH • scavengers. Keywords Contact glow discharge electrolysis  H • scavengers  Nonfaradaic yields  Primary radical yield Introduction Contact glow discharge electrolysis (CGDE) is a non-conventional electrolysis in which a luminous sheath of plasma is sustained by d.c. glow discharges between an electrode and the surface of the liquid electrolyte around it. The phenomenon also termed as plasma electrolysis develops spontaneously at either the anode or the cathode during conventional normal electrolysis (NE) at sufficiently high voltages in aqueous, non-aqueous or molten media. The electrode, where the current density is larger, the electrolyte resistivity is higher, or the electrolyte surface tension is lower, is the preferred location of CGDE. The threshold voltage for the onset of full CGDE, called the mid-point voltage, is 420 V for the anode and 160 V for the cathode in aqueous electrolytes [1, 2]. The detailed mechanism of the transition of NE-to-CGDE at the anode in an aqueous electrolyte has been elucidated as consisting of the following sequences: normal electrolysis, solvent vaporisation near the anode by Joule heating, setting up of stable counter flows between the vapour bubbles escaping away from the anode and the liquid anolyte moving towards it, collapse of this flow pattern and formation of an unstable vapour film over the anode with an overlying U. Gangal  M. Srivastava  S. K. Sen Gupta (&) Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India e-mail: sksbhuchem@yahoo.co.in 123 Plasma Chem Plasma Process (2010) 30:299–309 DOI 10.1007/s11090-010-9216-9