Cerium oxidising agent

During the addition of the cerium(IV) solution up to the equivalence point, its only effect will be to oxidise the iron(II) (since K is large) and consequently change the ratio [Fe3+]/[Fe2 + ], When lOmL of the oxidising agent have been added, [Fe3+]/[Fe2 + ] = 10/90 (approx.) and... 

The standard redox potential is 1.14 volts the formal potential is 1.06 volts in 1M hydrochloric acid solution. The colour change, however, occurs at about 1.12 volts, because the colour of the reduced form (deep red) is so much more intense than that of the oxidised form (pale blue). The indicator is of great value in the titration of iron(II) salts and other substances with cerium(IV) sulphate solutions. It is prepared by dissolving 1,10-phenanthroline hydrate (relative molecular mass= 198.1) in the calculated quantity of 0.02M acid-free iron(II) sulphate, and is therefore l,10-phenanthroline-iron(II) complex sulphate (known as ferroin). One drop is usually sufficient in a titration this is equivalent to less than 0.01 mL of 0.05 M oxidising agent, and hence the indicator blank is negligible at this or higher concentrations. 

Cerium(IV) sulphate is a powerful oxidising agent its reduction potential in... 

The advantages of cerium(IV) sulphate as a standard oxidising agent are ... 

With the exception of iron(II) and uranium(IV), the reduced solutions are extremely unstable and readily re-oxidise upon exposure to air. They are best stabilised in a five-fold excess of a solution of 150g of ammonium iron(III) sulphate and 150 mL of concentrated sulphuric acid per litre [approximately 0.3M with respect to iron] contained in the filter flask. The iron(II) formed is then titrated with a standard solution of a suitable oxidising agent. Titanium and chromium are completely oxidised and produce an equivalent amount of iron(II) sulphate molybdenum is re-oxidised to the Mo(V) (red) stage, which is fairly stable in air, and complete oxidation is effected by the permanganate, but the net result is the same, viz. Mo(III)- Mo(VI) vanadium is re-oxidised to the V(IV), condition, which is stable in air, and the final oxidation is completed by slow titration with potassium permanganate solution or with cerium(IV) sulphate solution. 

Of striking brevity is the direct addition of acetic acid to 1,1 -dichloro-4-methyl-penta-1,3-diene by means of one-electron oxidising agents like manganese (111) acetate [98], cerium(IV) [99] or vanadium(V) salts. [100,101] The further... 

Cerium(IV) is a strong oxidising agent and, as such, it has a number of chemical applications as an oxidant. In studying the hydrolysis of cerium(IV), a number of studies have utilised oxidation-reduction reactions in determining the relevant stability constants. As a tetravalent cation with a relatively small ionic radius, the hydrolysis of cerium(IV) occurs at very low pH. Consequently, data have been provided that show that the metal ion is extensively hydrolysed even at a pH of around 0 (i.e. Imoll" H" ) (Baes and Mesmer, 1976). Cerium(IV) is used as an analogue for plutonium(IV) in nuclear fuel manufacturing studies. 

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