Solubility products of silver halides

How can you explain the change in the colour of the silver halides with an increase in the atomic number of the halogen Compare the solubility products of silver halides and sulphide (see Appendix 1, Table 12). What anion is the most sensitive reagent for the silver ion What is the significance of silver halides in photography What substances are used in developing photographs ... 

Table 10. Solubility products of silver halides, and formation constants of dihalogenido complexes of the silver ion in various solvents...

J. Nedoma, Chem. Listy., 66, 772 (1972). Solubility products of silver halides in isopropyl alcohol and its mixtures with water. 

The solubility products of most halides are much higher in general than those of chalcogenides. Those of the silver halides are fairly low, which allows these depositions to take place readily. 

Traditionally, potentiometric sensors are distinguished by the membrane material. Glass electrodes are very well established especially in the detection of H+. However, fine-tuning of the potentiometric response of this type of membrane is chemically difficult. Solid-state membranes such as silver halides or metal sulphides are also well established for a number of cations and anions [25,26]. Their LOD is ideally a direct function of the solubility product of the materials [27], but it is often limited by dissolution of impurities [28-30]. Polymeric membrane-based ISEs are a group of the most versatile and widespread potentiometric sensors. Their versatility is based on the possibility of chemical tuning because the selectivity is based on the extraction of an ion into a polymer and its complexation with a receptor that can be chemically designed. Most research has been done on polymer-based ISEs and the remainder of this work will focus on this sensor type. 

In measurements with ion-selective electrodes, interference by other ions is expressed by selectivity coefficients as in Eq. (17). If the nature of the ion-selective membrane is known, these interferences may easily be estimated. For example, in the determination of chloride with a Cl -selective electrode containing AgCl as the electroactive component in its membrane, concentrations of bromides or iodides (generally X ) must be controlled because they form less soluble silver salts than AgCl the solubility products of corresponding silver halides are used in Eq. (20) to estimate the selectivity coefficient ... 

There are several other electrochemical measxirements in protic solvents which are of interest and have not been discussed above. In pure methanol, the data of Buckley and Hartley were noted to contain some errors and the values of for the silver halides must therefore be questioned. The solubility products of the silver halides have been redetermined more recently by potentiometric titration and these results are compared in Table 2.7.6. 

AgBr will be bromide selective, and so on. The selectivity observed with such silver halide precipitates follows exactly the solubility product of the respective silver salt. Consequently, the following sequence is always observed for any given silver precipitate membrane ... 

Due to the very weak values of silver halide s solubility products, titration reactions are quasi-totally displaced toward the right. This condition, which is required to carry out a good titration, is obeyed. 

The processes governing the endpoint indication are the successive precipitations of silver halide and silver chromate. The sensibility and accuracy of the endpoint indication depend on the concentration of chromate ions, which, in turn, depends on the total concentration of chromate ions and the pH value. Examining the solubility products permits us to determine the best experimental conditions. 

The activity of silver ions may be expressed in terms of the solubility product of the silver halide by... 

When halide abstraction reactions are performed with silver salts in water or in non-aqueous solutions, halide ions are abstracted according to the solubility product of the silver halide (Table 3.1) with the least soluble salts being the first to be precipitated. Abstraction follows the sequence I > Br> Cl" > F". Accordingly, then, the interaction of [NbCl2lCp2l with one mole equivalent of silver perchlorate in acetone leads to the formation of [NbCl2(Me2C0)Cp2][C104] and precipitation of Agl.22... 

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