Strong reducing agent

Europium(TTI) salts are typical lanthanide derivatives. Europium(ll) salts are pale yellow in colour and are strong reducing agents but stable in water. EuX2 are prepared from EuX -hEu (X=C1, Br, I) or EuFa + Ca EuCl2 forms a dihydrale. EUSO4 is prepared by electrolytic reduction of Eu(III) in sulphuric acid. Eu(II) is probably the most stable +2 stale of the lanthanides... 

Hypophosphorous acid, H3PO2, H2P(0)0H. A monobasic acid. Ba(H2P02)2 is formed when white phosphorus is dissolved in Ba(OH)2 solution. H3PO2 and its salts are strong reducing agents. 

Phosphorous acid, H3PO3, HP(0)(0H)2-A dibasic acid (PCI3 plus cold water), strong reducing agent. 

Tiianium ll) chloride, TiCl2- Black powder (TiCl4 plus Ti or heat on TiCl3). Strong reducing agent, immediately reduces water. Forms some complexes. 

Half-reaction (i) means that Co(II) in aqueous solution cannot be oxidised to Co(III) by adding ammonia to obtain the complexes in (ii), oxidation is readily achieved by, for example, air. Similarly, by adding cyanide, the hexacyanocobaltate(II) complex becomes a sufficiently strong reducing agent to produce hydrogen from water ... 

In the presence of strong reducing agents the sulphite ion acts as an oxidising agent some examples are ... 

Reduction of dichromate by strong reducing agents yields the chromiumfll) ion, Cr (see p. 383). 

Reductions. Hydrazine is a very strong reducing agent. In the presence of oxygen and peroxides, it yields primarily nitrogen and water with more or less ammonia and hydrazoic acid [7782-79-8]. Based on standard electrode potentials, hydrazine in alkaline solution is a stronger reductant than sulfite but weaker than hypophosphite in acid solution, it falls between and Ti ( 7). 

Potassium, Pubidium, and Cesium idjdrides. Although all the other alkah metal hydrides have been synthesized and some of the properties measured, only potassium hydride [7693-26-7] is commercially available. KH is manufactured in small amounts and sold as a mineral oil dispersion. It is a stronger base than NaH and is used to make the strong reducing agent KBH(C2H )2 and the super bases RNHK and ROK (6). 

The saline hydrides ate very reactive and ate strong reducing agents. AH saline hydrides decompose in water, often violently, to form hydrogen ... 

Phosphoric acid, aside from its acidic behavior, is relatively unreactive at room temperature. It is sometimes substituted for sulfuric acid because of its lack of oxidising properties (see SuLFURic ACID AND SULFURTRIOXIDe). The reduction of phosphoric acid by strong reducing agents, eg, H2 or C, does not occur to any measurable degree below 350—400°C. At higher temperatures, the acid reacts with most metals and their oxides. Phosphoric acid is stronger than acetic, oxaUc, siUcic, and boric acids, but weaker than sulfuric, nitric, hydrochloric, and chromic acids. 

Care must be exercised in using sodium nitrite near other chemicals. It is incompatible with ammonium salts, thiocyanates, thiosulfates, and strong reducing agents. In acid solutions, sodium nitrite evolves toxic NO in the presence of secondary amines it can form nitrosamines which are suspected carcinogens. 

A group of violet titanium(III) acylates has been prepared from TiCl and alkafl carboxylates. AH of the acylates are strong reducing agents similar to TiCl (189). Studies of Ti(III) compounds include the reaction (190)... 

The standard reduction potential of Cr " (Table 2) shows that this ion is a strong reducing agent, and Cr(II) compounds have been used as reagents in analytical chemistry procedures (26). The reduction potential also explains why Cr(II) compounds are unstable in aqueous solutions. In the presence of air, the oxidation to Cr(III) occurs by reaction with oxygen. However, Cr(II) also reacts with water in deoxygenated solutions, depending on acidity and the anion present, to produce H2 and Cr(III) (27,28). 

This process, based on strong reducing agents, can be avoided by the use of disperse dyes that are removed by aqueous alkaH alone. Two types of dye are used dyes containing diesters of carboxyHc acid and dyes destroyed by mild alkaH. The reaction of diester dyes is shown in equation 5. 

NaBH4, H0(CH2)20H, 40°, 18 h, 87% yield. Lithium aluminum hydride can be used to effect efficient ester cleavage if no other functional group is present that can be attacked by this strong reducing agent. ... 

Ascorbic acid is a reasonably strong reducing agent. The biochemical and physiological functions of ascorbic acid most likely derive from its reducing properties—it functions as an electron carrier. Loss of one electron due to interactions with oxygen or metal ions leads to semidehydro-L-ascorbate, a reactive free radical (Figure 18.30) that can be reduced back to L-ascorbic acid by various enzymes in animals and plants. A characteristic reaction of ascorbic acid is its oxidation to dehydro-L-aseorbie add. Ascorbic acid and dehydroascor-bic acid form an effective redox system. 

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