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A nitrite test is a standard component of a urinary test strip. A positive test for nitrites in the urine is called nitrituria. This test is commonly used in diagnosing urinary tract infections (UTIs). A positive nitrite test indicates that the cause of the UTI is a Gram-negative organism, most commonly Escherichia coli. The reason for nitrites ...
In organic chemistry, an azo coupling is an reaction between a diazonium compound (R−N≡N +) and another aromatic compound that produces an azo compound (R−N=N−R’).In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile, and the activated carbon (usually from an arene, which is called coupling agent), serves as a nucleophile.
Therefore, they are used as dyes, and are commonly known as azo dyes, an example of which is Disperse Orange 1. Some azo compounds, e.g., methyl orange, are used as acid-base indicators due to the different colors of their acid and salt forms. Most DVD-R/+R and some CD-R discs use blue azo dye as the recording layer. The commercial success of ...
2) is a weak and monoprotic acid known only in solution, in the gas phase, and in the form of nitrite (NO − 2) salts. [3] It was discovered by Carl Wilhelm Scheele, who called it "phlogisticated acid of niter". Nitrous acid is used to make diazonium salts from amines. The resulting diazonium salts are reagents in azo coupling reactions to ...
To prevent future buildup of extrinsic stains, identification of the cause (e.g., smoking) is required. Intrinsic discoloration generally requires one of the many types of tooth bleaching . Alternatively the appearance of the tooth can be hidden with dental restorations (e.g., composite fillings, veneers , crowns).
It is commonly found between the teeth, on the front of teeth, behind teeth, on chewing surfaces, along the gumline (supragingival), or below the gumline cervical margins (subgingival). [1] Dental plaque is also known as microbial plaque, oral biofilm, dental biofilm, dental plaque biofilm or bacterial plaque biofilm.
Phenazopyridine is an azo dye. [17] [18] Other azo dyes, which were previously used in textiles, printing, and plastic manufacturing, have been implicated as carcinogens that can cause bladder cancer. [19] While phenazopyridine has never been shown to cause cancer in humans, evidence from animal models suggests that it is potentially ...
For example, ethyl formate or orthoformate reacts with two equivalents of phenylhydrazine to yield 1,5-diphenylformazan, under acidic conditions. Under basic conditions, ethyl nitrate reacts at the methylene position to yield 3-methyl-1,5-diphenylformazan, which can also be obtained from the reaction of phenylazoethane with isoamyl nitrite .