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For example, the electrolysis of brine produces hydrogen and chlorine gases which bubble from the electrolyte and are collected. The initial overall reaction is thus: [22] 2 NaCl + 2 H 2 O → 2 NaOH + H 2 + Cl 2. The reaction at the anode results in chlorine gas from chlorine ions: 2 Cl − → Cl 2 + 2 e −
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.
For example, if one molecule of hydrogen results from every two electrons inserted into an acidic solution then the faradaic efficiency would be 100%. This indicates that the electrons did not end up performing some other reaction. For example, the oxidation of water will often produce oxygen as well as hydrogen peroxide at the anode. Each of ...
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 −
At the anode (A), chloride (Cl −) is oxidized to chlorine. The ion-selective membrane (B) allows the counterion Na+ to freely flow across, but prevents anions such as hydroxide (OH −) and chloride from diffusing across. At the cathode (C), water is reduced to hydroxide and hydrogen gas. The net process is the electrolysis of an aqueous ...
English chemist John Daniell (left) and physicist Michael Faraday (right), both credited as founders of electrochemistry.. Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference and identifiable chemical change.
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 ...