Andrews titration

As an oxidant, V(V) is comparable to dichromate, but is less subject to interference from organic compounds than is dichromate or Ce(IV). Thus phenol and o-, m-, and p-cresols interfere with the titration of hydroquinone with CeflV), but V(V) gives the correct result It has been used as a substitute for iodate in the Andrews titration (Section 20-1) in 7 Af hydrochloric acid, in the presence of iodine monochloride. ... 

Write an equation for the oxidation of Cu(I) thiocyanate in the Andrews titration. 

Determination of available oxygen in pyrolusiie by KIO (Andrews titration)... 

Hydrazine and its salts can be titrated in solution using manganese(lll) solutions. Saits of hydrazine generally act as reductants and they can be titrated by suitable redox titrations. Under Andrews titration conditions, iodate is reduced to ICI (I2 is initially liberated). Hydrazine salts can be titrated against standard KIO3 solution. 

The iodide solution is analysed for iodide by Andrews titration (Sec.8.3.3) ie titration in presence of cone. HCl and a small amount of an organic liquid to indicate the endpoints. 

In the alternative determination, the iodide from Snl4 is oxidised by iodate to ICl (Andrews titration conditions, 8ec.8.3.3). 

Andrews deration An important titration for the estimation of reducing agents. The reducing agent is dissolved In concentrated hydrochloric acid and titrated with potassium iodale(V) solution. A drop of carbon tetrachloride is added to the solution and the end point is indicated by the disappearance of the iodine colour from this layer. The reducing agent is oxidized and the iodate reduced to ICl, i.e. a 4-eiectron change. 

Kies141 made an extensive study of oxidimetric titrations of iodide with iodate according to Andrews in the presence of hydrochloric acid. The shape (in 1N HC1) of the two hyperbolic sections followed by a flat part of the curve is explained by the occurrence of two (nearly) reversible systems, I2C1 /I and IC12 /I2C1 , according to the titration reactions... 

Fig. 3.82. Dead-stop end-point titration of (5 ml 0.0983 M) I with (0.01662 M) I03 in 1 iV HC1 by Kies (titration reactions according to Andrews).

Andrews introduced the titration, further developed by Jamieson," in which potassium iodate is used as a titrating reagent. In 3 to 9 Af hydrochloric acid, iodate is reduced to iodine monochloride ... 

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