Anodic behaviour at tin and aluminium electrodes

A number of techniques have been used to study the anodic behaviour of tin and aluminium in some aqueous electrolytic solutions. In acidic solution the dissolution of tin is relatively fast. The reaction mechanism in perchlorate electrolyte corresponds to two consecutive one-electron steps of comparable rate. In chloride electrolyte the most appropriate mechanism involves simultaneous two-electron transfer. The order of reaction with respect to chloride ion is unity. The measured currents are also dependent upon the concentration of hydrogen ion. The active dissolution of tin in sodium hydroxide solution is relatively fast with an order of reaction with respect to hydroxyl ion of two. The mechanism involves a following chemical reaction to form stannite ions. [Continues.]