Electrolysis of aqueous sodium chlorid

The fluoride and chloride ions are very difficult to oxidize (Elx F = —2.889 V E°x Cl- = —1.360 V). Hence the elements fluorine and chlorine are ordinarily prepared by electrolytic oxidation, using a high voltage. As pointed out in Chapter 18, chlorine is prepared by the electrolysis of aqueous sodium chloride ... 

The term chlor-alkali refers to those products obtained from the commercial electrolysis of aqueous sodium chloride. These are chlorine, sodium hydroxide, and sodium carbonate. The first two are produced simultaneously during the electrolysis while the latter is included because it is also produced in small quantities and shares many of the end uses of sodium hydroxide. Perfluorinated ionomer membranes are permeable to sodium ions but not the chloride ions, and hence they are useful for these electrolytic cells. The arrangement of a typical membrane cell is shown in Figure 10.2. 

The electrolysis of aqueous sodium chloride is used to prepare chlorine, sodium, and hydrogen. 

When an aqueous salt solution is electrolyzed, the electrode reactions may differ from those for electrolysis of the molten salt because water may be involved. In the electrolysis of aqueous sodium chloride, for example, the cathode half-reaction might be either the reduction of Na+ to sodium metal, as in the case of molten sodium chloride, or the reduction of water to hydrogen gas ... 

The observed electrode reactions and overall cell reaction for electrolysis of aqueous sodium chloride are... 

Production of chlorine and sodium hydroxide by electrolysis of aqueous sodium chloride is the basis of the chlor-alkali industry, a business that generates annual sales of approximately 4 billion in the United States alone. Both chlorine and sodium hydroxide rank among the top 10 chemicals in terms of production Annual output of each in the United States is 11-12 million tons. Chlorine is used in water and sewage treatment and in the manufacture of plastics such as poly(vinyl chloride) (PVC). Sodium hydroxide is employed in making paper, textiles, soaps, and detergents. 

Electrolysis of aqueous sodium chloride (brine) is an important industrial process for the production of chlorine and sodium hydroxide. In fact, this process is second only to the production of aluminum as a consumer cf electricity in the United States. Sodium is not produced in this process under normal circumstances because H20 is more easily reduced than Na+, as the standard reduction potentials show ... 

Chlorine (0.19% of lithosphere) is produced mainly from NaCl which is either crystallised from brines or mined. The gas is a product of the electrolysis of aqueous sodium chloride for caustic soda production, with carbon anodes and a mercury cathode. It is also a by-product of the manufacture mainly of metallic sodium, but also of magnesium and calcium, by electrolysing the appropriate fused chloride. Its chief uses are as a bleach, a bactericide, and an industrial chemical. 

Since ca. 97% of the chlorine is produced from the electrolysis of aqueous sodium chloride solution, the linked products sodium hydroxide and hydrogen are produced as byproducts ... 

Almost the whole production of chlorine is produced by the electrolysis of aqueous sodium chloride solutions. Only a small part is obtained by the electrolysis (or oxidation) of hydrochloric acid (or hydrogen chloride) (see Section 1.7.3). Small quantities of chlorine are also produced in the electrochemical manufacture of metals such as sodium. 

In this chapter, roughly one dozen quite different production processes will be summarized. For instance, the most important electrochemical process, the electrolysis of aqueous sodium chloride leading to chlorine, alkali, hydrogen, and chlorine oxygen compounds are incorporated (Sect. 5.2). Other processes are carried out in a small scale only, but have an unchallenged place in the technical chemistry, for instance, the generation of molecular fluorine (Sect. 5.3). Others are of limited importance nowadays, but may gain importance in the future, for example, the electrolysis of water (Sect. 5.4). 

A cell similar in principle to the diaphragm cell described above and operated without a diaphragm gives the same initial products but allows these to react with each other (Eqs. 8.24, 8.12-8.16). This is the basis of the chlorate cell. The initial electrochemical products ultimately form sodium chlorate as the final cell product from the electrolysis of aqueous sodium chloride [11]. Part of the product formation involves the chemical chlorate formation just outlined (Eqs. 8.12-8.16), and part of it forms from electrolytic chlorate formation (Eq. 8.28). 

The electrochemical synthesis of chlorine takes place through the electrolysis of aqueous sodium chloride. The electrode reactions are ... 

The term chlor-alkali refers to those products obtained from the commercial electrolysis of aqueous sodium chloride. These are chlorine, sodium hydroxide, and sodium carbonate. The first two... 

The electrolysis of aqueous sodium chloride (brine) is an important industrial process for the production of chlorine and sodium hydroxide. In fact, this process is the... 

Chlorine gas is used to disinfect drinking water and sewage, and in the production of organic chemicals such as pesticides and vinyl chloride, the building block of plastics called polyvinyl chlorides (PVGs, Section 14.5). Chlorine gas is commonly among the top chemicals produced each year in the United States. Almost all chlorine gas is made by electrolysis of aqueous sodium chloride. The other product of sodium chloride electrolysis, sodium hydroxide, is equally valuable because it is the most commonly used base in industrial processes. The reaction in electrolysis of aqueous NaCl is... 

The electrolysis of aqueous sodium chloride, normally brine obtained directly from natural salt deposits, to yield chlorine, sodium hydroxide and hydrogen is the largest of the electrolytic industries. In the USA, the annual production of chlorine is of the order of 10 tons while in the UK it is about 1.7 x 10 tons. 

A (a) Metallic magnesium cannot be obtained by electrolysis of aqueous magnesium chloride, MgCb. Why (b) There are no sodium ions in the overall cell reaction for the electrolysis of aqueous sodium chloride. Why ... 

Chlorine is produced industrially on a large scale in the Chloralkai process, electrolysis of aqueous sodium chloride or natural brine solutions. The most commonly employed cell uses an asbestos diaphragm to separate the chlorine gas formed at the cathode from the sodium hydroxide (NaOH) that concentrates in the residual solution ... 

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