Electrolysis of aqueous NaCl solution

Sonoelectrochemical destruction of dyes has also been investigated. Solutions of the acidic dye Sandolan Yellow have been decolourised by a sonoelectrochemical process in aqueous saline solution using platinum electrodes [42]. The process entails the electrolysis of aqueous NaCl solution which involves the liberation of chlorine at the anode and hydroxide ion at the cathode. The overall cell reaction is ... 

On the other hand, application of alkali metal amalgam permits the slowing down of the reaction of metals with alcohols, which is used in the industrial production of alkali metals alkoxides. Production of NaOR by Mathieson Alkali Works is based, for instance, on the reaction of sodium amalgam (formed as a result of the electrolysis of aqueous NaCl solution with the mercury cathode) with alcohol NaOR ROH is isolated from the solutions. Na residue in the amalgam is hydrolyzed, the obtained mixture is returned to the electrolyz-... 

Finally, a preparation of hydrogen that is of considerable importance is the electrolysis of aqueous NaCl solutions ... 

Figure 21-3 Electrolysis of aqueous NaCl solution. Although several reactions occur at both the anode and the cathode, the net result is the production of H2(g) and NaOH at the cathode and Cl2(g) at the anode. A few drops of phenolphthalein indicator were added to the solution. The solution turns pink at the cathode, where OH ions are formed.

Chlo-alkali process. The production of chlorine gas by the electrolysis of aqueous NaCl solution. (21.6)... 

KCIO3. Not very soluble in water, deposited from chlorate(V) solutions (CI2 plus Ca(OH)2 or electrolysis of aqueous NaCl). On heating gives KCl and KCIO4 but decomposes to KCl at high temperatures. 

Large amounts of aqueous sodium hypochlorite (NaOCl) are produced in the chlor-alkali industry (Section 18.12) when the Cl2 gas and aqueous NaOH from the electrolysis of aqueous NaCl are allowed to mix. Aqueous NaOCl is a strong oxidizing agent and is sold in a 5% solution as chlorine bleach. 

Generated by electrolysis of aqueous NaCl to produce electrolyzed basic solution at cathode and electrolyzed acidic solution at anode... 

The properties of sodium hydroxide and potassium hydroxide are very similar. These hydroxides are prepared by the electrolysis of aqueous NaCl and KCl solutions (see Section 19.8) both hydroxides are strong bases and very soluble in water. Sodium hydroxide is used in the manufacture of soap and many organic and inorganic compounds. Potassium hydroxide is used as an electrolyte in some storage batteries, and aqueous potassium hydroxide is used to remove carbon dioxide and sulfur dioxide from air. 

The cathodic solution prepared by the electrolysis of an NaCl solution showed a strong antioxidant activity on flie aqueous oxidation of polyunsaturated fatty acid esters, squalene, vitamin A and P-carotene. Although the mechanism for the antioxid t effect of the cathodic solution has not been fully elucidated, the effect would be partly due to radical scavenging ability and/or alkaline molecules formed in the cathodic solution. On the other hand, the antioxidant activity of the cathodic solution has not been found on phosphatidylcholine, free fatty acids and a-tocopherol. The different effect of the cathodic solution on the oxidation of polar lipids may be correlated witii the ionization of these lipids in the cathodic solution. 

Chlorine and caustic soda are coproducts of electrolysis of aqueous solutions of sodium chloride [7647-14-5] NaCl, (commonly called brine) following the overall chemical reaction... 

Explosion Hazards. The electrolysis of aqueous solutions often lead to the formation of gaseous products at both the anode and cathode. Examples are hydrogen and chlorine from electrolysis of NaCl solutions and hydrogen and oxygen from electrolysis of water. The electrode reactions. 

Cataldo F (1992) Effects of ultrasound on the yield of hydrogen and chlorine during electrolysis of aqueous solutions of NaCl or HC1. J Electroanal Chem 332 325-331... 

Chlorine (Cl ) and sodium hydroxide (NaOH) are two important chemicals produced by electrolysis. Chlorine and sodium hydroxide are generally among the top ten chemicals produced annually in the United States. The electrolysis of brine or aqueous NaCl solution is used to produce chlorine, sodium hydroxide, and hydrogen (Figure 14.14). The chloride ion in the brine solution is oxidized at the anode, while water is converted at the cathode according to the following reactions ... 

Since chemical reduction means gain of electrons, electrolysis is the most direct way of recovering a metal from its ores, as long as these can be handled in a fluid state.6 Consideration of E° values for reactive metal halfcells such as Na+(aq)/Na(s), Mg2+(aq)/Mg(s), and Al3+(aq)/Al(s) (-2.71, -2.36, and -1.67 V, respectively) shows that these metals can never be obtained by electrolysis of aqueous solutions of their salts, as H2 would be produced instead, but they can often be obtained by electrolysis of suitable molten salts such as NaCl and MgCl2 ... 

Chloride ions are obviously being oxidized to CI2 in this cell, as they were in the electrolysis of molten NaCl. But Na+ ions are not reduced to metallic Na. Instead, gaseous H2 and aqueous OH ions are produced by reduction of H2O molecules at the cathode. Water is more easily reduced than Na+ ions. This is primarily because the reduction of Na+ would produce the very active metal Na, whereas the reduction of H2O produces the more stable products H2(g) and OH (aq). The active metals Ei, K, Ca, and Na (Table 4-12) displace H2 from aqueous solutions, so we do not expect these metals to be produced in aqueous solution. Later in this chapter (Section 21-14) we learn the quantitative basis... 

The overall cell reaction produces gaseous H2 and CI2 and an aqueous solution of NaOH, called caustic soda. Solid NaOH is then obtained by evaporation of the residual solution. This is the most important commercial preparation of each of these substances. It is much less expensive than the electrolysis of molten NaCl, because it is not necessary to heat the solution. 

Chlorine gas, CI2, is prepared industrially by the electrolysis of molten NaCl (see Section 19.8) or by the chlor-alkali process, the electrolysis of a concentrated aqueous NaCl solution (called brine). Chlor denotes chlorine and alkali denotes an alkali metal, snch as sodium.) Two of the common cells nsed in the chlor-alkali process are the mercnry cell and the diaphragm cell. In both cells the overall reaction is... 

J89 (a) What is electrolysis (b) Arc electrolysis reactions thermodynamically spontaneous Explain, (c) What process occurs at the anode in the electrolysis of molten NaCl (d) Why is sodium metal not obtained when an aqueous solution of NaCl undergoes electrolysis ... 

Section 23.4 Electrometallurgy is tire use of electrolytic methods to prepare or purify a metallic element. Sodium is prepared by electrolysis of molten NaCl in a Downs cell. Aluminum is obtained in the Hall process by electrolysis of AI2O3 in molten cryolite (NagAlFg). Copper is purified by electrolysis of aqueous copper sulfate solution using anodes composed of impure copper. 

Both I2 and Bt2 are commercially prepared by oxidation of their halide binary salts from oceans or natural waters, and CI2 can be prepared by electrolyzing aqueous NaCl solutions. Why then is it not possible to prepare F2 by electrolysis of an aqueous NaF solution ... 

Briefly explain why different products are obtained from the electrolysis of molten NaCl and the electrolysis of a dilute aqueous solution of NaCl. 

Due to the cost of electricity, this reaction is not economically feasible when more than a very small amount of hydrogen is required. However, electrolysis does become economically viable on an industrial scale when the hydrogen is produced as a byproduct of the electrolysis of concentrated aqueous NaCl solutions during the production of NaOH and chlorine. ... 

---