Color indicator mixed indicators

Mixed indicators give sharp color changes and are especially useful in titrating to a given titration exponent (p7). 

Methyl green, hexamethylpararosaniline hydroxymethylate (component of mixed indicator) dissolve 0.1 g in 100 mL alcohol when used with equal parts of hexamethoxytriphenyl carbinol gives color change from violet to green at a titration exponent (pi) of 4.0. 

Mixed Indicator Acid Color Base Color pH Range... 

Size polymers on polyester can be determined by staining tests with Cl Basic Red 22, Cl Reactive Red 12, iodine/potassium iodide solution, or a mixed indicator. The extraction of size components and their determination in solution using a variety of reagents to give a characteristic coloration or a coloured precipitate has been described. Methods using fluorescence spectroscopy with a fluorescent cationic dye (e.g. Pinacryptol Yellow or Cl Basic Orange 14) were also described. 

Test Ttibe 3 6 M NH3 1 carefully smelled all tubes to begin with and this tube was definitely ammonia. Since I was able to rule out this tube initially, I then mixed a small amount of known ammonia with all other tubes. As I mixed the ammonia with the other tubes, I noticed considerable heat being produced in tubes 1, 4 and 7, which I suspected was due to an acid present. With tube 1, smoke appeared, which led me to believe that tube 1 was the HC1 which produced a white cloud (smoke) of NH4C1. Tubes 1 and 3 were now ruled out. I then noticed precipitates formed in tubes 8 (blue), tube 6 (blue), tube 5 (white), tube 10 (brownish-grey) and tube 7 (white). When excess ammonia was added to tube 10, the precipitate dissolved. When excess ammonia was added to test tube 8, the precipitate dissolved and the solution turned dark blue indicative of Cu2+. When I added excess ammonia to test tube 6, the precipitate dissolved and the solution turned a medium blue color, indicative of the presence of Ni(NH3)62+. 

The macrocydic polyether BPP34C10 and 1,1 -dimethyl-4,4-bipyridiniumbis(hexafluorophosphate) give rise to colorless solutions when they are dissolved by them-sdves in MeCN. The sudden appearance of a color, upon mixing the two compounds in MeCN, is indicative of complex formation and is a result of chaige transfer interadions between the complementaiy aromatic units of the host and guest. 

Using a color indicator which shows when the concentration of A falls below 0.1 mol/liter, the following scheme is devised to explore the kinetics of the decomposition of A. A feed of 0.6 mol A/liter is introduced into the first of the two mixed flow reactors in series, each having a volume of 400 cm. The color change occurs in the first reactor for a steady-state feed rate of 10 cmVmin, and in the second reactor for a steady-state feed rate of 50 cm /min. Find the rate equation for the decomposition of A from this information. 

Ammonium chloride is analyzed by treatment with formaldehyde (neutralized with NaOH) and the product HCl formed is analyzed by titration using an acid-base color indicator such as phenolphthalein. Alternatively, it may be mixed with caustic soda solution and distdled. The distillate may be analyzed for NH3 by titration with H2SO4 or by colorimetric Nesslerization or with an ammonia-selective electrode (APHA, AWWA, WEF. 1995. Standard Methods for the Examination of Water and Wastewater. 19th ed. Washington, DC, American Pubhc Health Association). The presence of ammonia or any other ammonium compound would interfere in the test. The moisture content in NH4CI may be determined by Karl—Fischer method. 

Transfer 150 ml of the silver nitrate reagent to each of two 250-ml glass-stoppered Erlenmeyer flasks. Place the flasks in a suitable ice bath until, die temperature of the contents Is 32°to 39.2 F (0° to 4°C). Add 7 to 9 drops of the mixed indicator to each flask and, if necessary, neutralize to a gray-green color with 0.02N sodium hydroxide if. acid or with 0.02N nitric acid if alkaline. Reserve one of the flasks for the blank and into the second flask pour 0 ml of propellant. Compare the color of the sample with that of the blank. A purple color in the sample solution indicates... 

Mixing time 6 is the time necessary to completely homogenize an admixture with the liquid contents of the vessel. It can easily be determined visually by a decolorization reaction (neutralization, redox reaction in the presence of a color indicator). The relevance list of this task consists of the target quantity (mixing time 6) and of the same parameters as in the case of mixing power— on condition that (contrary to Example 3) both liquids have similar physical properties ... 

Bromcresol green, 0.1%, and methyl red, 0.01%, each in 96% ethanol mix in a volume ratio of 1 2. [A stronger methyl red stock solution (2) is difficult to prepare.] The working solution, which is stable indefinitely, is made by adding 12 ml of the mixed indicator per 100 ml of the boric acid. Only exceptionally need adjustment to the desired reddish-purple color be performed, by adding drops of acid or alkali. 

Demonstrations with universal indicator (a mixed indicator with many color changes) are described in J. T. Riley, Flashy Solutions, J. Chem. 

Color Plate 5 Indicators and Acidity of C02 (Demonstration 11-1) (a) Cylinders before adding Dry Ice. Ethanol indicator solutions of phenolphthalein (left) and bromothymol blue (right) have not yet mixed with entire cylinder. 

The presence of peroxides in an organic liquid may be detected by the development of an intense brown color when a few drops of aqueous sodium iodide solution are mixed with a few milliliters of the liquid. A more quantitative method involves adding 1 mL of the liquid to an equal volume of a 10% sodium iodide in glacial acetic acid solution. A yellow color indicates a low peroxide concentration, whereas a brown color indicates a high peroxide concentration. 

Hue. Hue refers to the quality of a color that we indicate by its name, such as red, orange, green, and blue. To change the hue of a color, it must be mixed with another hue (e.g., to change yellow to yellow-green some blue must be added). 

This method is based on the titration of basic ammonia with standard sulfuric acid using methyl red-methylene blue indicator to pale lavender end point. Distill 100 mL sample into 50 mL boric acid mixed indicator solution. Titrate ammonia in this distillate solution with standard H2S04 (0.02 N) until the color turns to pale lavender. Perform a blank titration using distillate obtained from reagent grade water under similar conditions. Calculate the concentration of NH3-N in the sample as follows ... 

Components of mixed indicator Parts Transition Color change ... 

NH4 is distilled after alkalinization. Titration with standardized 0.01 M H2S04 and a mixed indicator (methylene blue and methylene red) NHJ is distilled from water after alkalinization. Ammonium reacts with Nessler s reagent (I2Hg—2IK) to form a yellow-brown colored complex (410—425 nm)... 

Alkalinity co - I ICO, Acid-base titration Titrating with standardized 0.01 M H2S04 using phenolphthalein as indicator until the pink color disappears at about pH 8.3 titration of the same sample is then continued until the end point is reached at pH 4.5 using a bromocresol green-methyl red mixed indicator (total alkalinity) Applicable to natural and waste water. Concentrations of bicarbonate, carbonate, and hydroxide can be calculated. The titration end points can be measured potentiometrically 50,51,67-69... 

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