There are a mytiad of applications of electrochemistry. From analytical measurement to industrial production of chemicals, batteries and fuel cells the chemical technology of electrochemistry has a for reaching impact. We will begin with a very basic application, which is also useful for helping to keep polarity conventions in mind. Electroplaying is an electrolytic application meaning that we must supply a voltage to drive the process of plating uut of a metal from its ions in solution. Metals such as Cu, Ag Au, and Cr are plated onto surfaces uses this process. This process works the best if a metal object can itself be made into the cathode. Then the plating will be relatively uniform over the surface. One reason for starting with this reaction is that it is easy to visualize the fact that the cathode is negative for an electroplating reaction. The negative polarity of the cathode is necessary to attract the cations and to get them to plate out on the surface.If you remember this then you know that the cathode has a negative polarity in an electrolytic cell. Thus, the anode has a postive polarity in an electrolytic cell. The polarities are opposite in a Galvani/Boltaic cell. THe negative polarity of the cathode in the electroplating reaction gives you a good way to remember all of the polarities by process of deduction.
Batteries are Voltaic cells. The technology of batteries is a hot topic today. Many kinds of alternative energy rely an efficient technology for barriers. Thus, the prize for developing cheap rechargeble, and eco-friendly batteries is enormous. This is an area of intensive research. This presentation discusses conventional battery technology in order to give you an idae how things work in your everyday life. Electrochemistry as at work every time you start a car and in many devices that you use. The lead sulfate battery (car battery is described as well as the Zn/Mn battery and alkaline battery variant that has become popular due to its longer life.
The electrolysis of water, also known as the process of water splitting, is a holy grail of current electorchemical technology. the reaction is quite feasible, but the goal is couple water spiltting with renewable energy. For example, could one use solar energy to promote electrons to the conduction band in a semi-conductor electrode and then efficiently use the energy captured by this process to reduce H+ to H2? Or could one use natural chemical processes to couple to the process and thereby convert an abundant natural source of chemical energy into hydrogen gas. The use of H2 gas a fuel is also a goal. The problems are safetyand conveniency. Since H2 is a gas one does not want to have a huge tank and it is always a concern if there is high pressure H2 gas that could pose a risk of explosion. Don't forget the HIndenberg! Of course, the Hindgerg was not even high pressure H2 gas, but the sheer quantity of gas created an enormous explosion.
Cells use redox chemistry to couple light harvesting in photosynthesis to energy capture using chemical means. Cells also store energy in a proton gradient, which essentially the same as a concentration cell. Although there are no electrodes in cells, the electron transport chain in both photosynthesis and respiration is best described in terms of the reduction potentials of the various steps. These potentials and their interpretation are discussed in the next video.
A concnetration cell is one, in which the reduction reaction is the same at both electrodes. The entire cell potential arises simply due to the difference in the concnetration of the ions in solution in the two cell compartments. Because it is the concentration difference (in the reaction quotient of the Nernst equation) that gives rise to the whole cell potential, we call such a cell a concentration cell.
