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Potassium chromate is added as indicator in an Erlenmeyer flask and the end of the reaction is determined by the slight red color given by the silver chromate. In the Mohr method, named after Karl Friedrich Mohr, potassium chromate is an indicator, giving red silver chromate after all chloride ions have reacted: 2Ag + (aq) + CrO 2−
Predominance diagram for chromate. The chromate ion is the predominant species in alkaline solutions, but dichromate can become the predominant ion in acidic solutions. Further condensation reactions can occur in strongly acidic solution with the formation of trichromates, Cr 3 O 2− 10, and tetrachromates, Cr 4 O 2− 13. [2]
The reactivity of the chromate anion with silver is lower than with halides (e.g. chlorides) so that in a mixture of both ions, only silver chloride precipitate will form: [9] AgNO 3(aq) + Cl − (aq) + CrO 2− 4(aq) → AgCl (s) + CrO 2− 4(aq) + NO − 3(aq) Only when no chloride (or any halogen) is left will silver chromate form and ...
Potassium dichromate, K 2 Cr 2 O 7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health.
Barium chromate has been found to be useful in many capacities. The compound is often used as a carrier for the chromium ions. One such case is the use of barium chromate as a sulfate scavenger in chromium electroplating baths. [5] Over time the chromium concentration of the bath will decrease until the bath is no longer functional.
Complexometric titrations are particularly useful for the determination of a mixture of different metal ions in solution. An indicator capable of producing an unambiguous color change is usually used to detect the end-point of the titration. Complexometric titrations are those reactions where a simple ion is transformed into a complex ion and ...
Lead(II) chromate can be produced by treating sodium chromate with lead salts such as lead(II) nitrate or by combining lead(II) oxide with chromic acid. Related lead sulfochromate pigments are produced by the replacement of some chromate by sulfate, resulting in a mixed lead-chromate-sulfate compositions Pb(CrO 4) 1−x (SO 4) x. This ...
A complexometric indicator is an ionochromic dye that undergoes a definite color change in presence of specific metal ions. [1] It forms a weak complex with the ions present in the solution, which has a significantly different color from the form existing outside the complex. Complexometric indicators are also known as pM indicators.