Search results
Results from the WOW.Com Content Network
The terms anode and cathode are not defined by the voltage polarity of electrodes, but are usually defined by the direction of current through the electrode. An anode usually is the electrode of a device through which conventional current (positive charge) flows into the device from an external circuit, while a cathode usually is the electrode through which conventional current flows out of ...
The purpose of the divided cell is to permit the diffusion of ions while restricting the flow of the products and reactants. This separation simplifies workup. An example of a reaction requiring a divided cell is the reduction of nitrobenzene to phenylhydroxylamine, where the latter chemical is susceptible to oxidation at the anode.
An electrolytic cell is an electrochemical cell that utilizes an external source of electrical energy to force a chemical reaction that would otherwise not occur. [ 1 ] : 64, 89 [ 2 ] : GL7 The external energy source is a voltage applied between the cell's two electrodes ; an anode (positively charged electrode) and a cathode (negatively ...
Electrolytic cell producing chlorine (Cl 2) and sodium hydroxide (NaOH) from a solution of common salt. For example, in a solution of ordinary table salt (sodium chloride, NaCl) in water, the cathode reaction will be 2 H 2 O + 2e − → 2 OH − + H 2. and hydrogen gas will bubble up; the anode reaction is 2 NaCl → 2 Na + + Cl 2 + 2e −
In this example, the anode is the zinc metal which is oxidized (loses electrons) to form zinc ions in solution, and copper ions accept electrons from the copper metal electrode and the ions deposit at the copper cathode as an electrodeposit.
An electrolytic cell is an electrochemical cell in which applied electrical energy drives a non-spontaneous redox reaction. [5] A modern electrolytic cell consisting of two half reactions, two electrodes, a salt bridge, voltmeter, and a battery. They are often used to decompose chemical compounds, in a process called electrolysis.
Carbon materials are not suitable for the anode side because of their degradation by HO-ions, which are nucleophiles. [11] On the cathode, nickel, titanium, and carbon can be readily used. The catalyst layer is typically made by mixing catalyst powder and ionomer to produce an ink or slurry that is applied by spraying or painting.
Furthermore, there is often more than one possible reaction at the surface of an electrode. For example, during the electrolysis of water, the anode can oxidize water through a two electron process to hydrogen peroxide or a four electron process to oxygen. The presence of an electrocatalyst could facilitate either of the reaction pathways.