some car manufactures use aluminium car body on a steel sub-frame. explain, using electrode potential what would happen if a weak acid was to become trapped in the space between these two metals!! any current plzz help, its for my assignment, and i dont understand
Most reactive metal will corrode first.
Do a google search for electrolysis of an acid.
Chemistry is all about how atoms exchange electrons. Some kinds like electrons better than others, and this is the basis of electrochemistry and Redox reactions. It all starts with the acid: HAcid - H(+) + Acid(-) The important thing is the H(+) ion, which is positive because it is a Hydrogen atom which has lost an electron. This leaves it with a positive charge, since it is nothing but a positive proton at this point. Fe + 2H(+) - Fe(+2) + H2 The above is a typical reaction between an acid and most metals. The H(+) ions strip an electron from the metal to form a metal ion and Hydrogen gas. What has happened is the Hydrogen ions have oxidized the Iron. The Iron in turn has reducted the Hydrogen. In terms of electrochemistry, there are two half reactions going on simutaneously. First, the Iron atoms generate two negative electrons: Fe - Fe(+2) + 2e(-) = OXIDATION OF IRON Then the Hydrogen ions combine with the electrons to form Hydrogen gas: 2H(+) + 2e(-) - H2 = REDUCTION OF HYDROGEN Note that in both reactions, the charges are equal on either side of the reaction. The next part of this process happens when the Iron ions come into contact with the Aluminum metal: 3Fe(+2) + 2Al - 2Al(+3) + 3Fe Note the Iron ions are recting exactly the same way the Hydrogen ions did. In other words, they are oxidizing the Aluminum. The Aluminum is now reducing the Iron. The net result of this is that the acid rusts the Iron and then the Iron rusts the Aluminum. The end result is the production of tiny amounts of Hydrogen gas, The Iron being displaced from where it had initially been, and the solid Aluminum discintegrating into some form of Aluminum salt. Calculations involve something called an electrochemical series and the voltage is given using the Nerst equation. Both the electrochemical table and the equation can be found in any chemistry textbook.
