Search results
Results from the WOW.Com Content Network
As long as the enzyme survives, the reaction of heme with peroxide is catalytic, making this test very sensitive to small quantities of blood present on the test swab. The hemoglobin-catalyzed reduction of peroxide that occurs is shown in the reaction below. The two electrons are supplied by phenolphthalein: HOOH + 2 e − + 2 H + → 2 H 2 O
Phenolphthalein's pH sensitivity is exploited in other applications: concrete has naturally high pH due to the calcium hydroxide formed when Portland cement reacts with water. As the concrete reacts with carbon dioxide in the atmosphere, pH decreases to 8.5–9. When a 1% phenolphthalein solution is applied to normal concrete, it turns bright pink.
A well-known application of this reactivity is the preparation of the anthraquinone dye quinizarin by reaction with para-chlorophenol followed by hydrolysis of the chloride. [7] Phenolphthalein can be synthesized by the condensation of phthalic anhydride with two equivalents of phenol under acidic conditions (hence
Chemical structure of phenolphthalein, a common phthalein dye. Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH. [1] They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes. Common phthalein dyes include ...
Solution: The main components of a universal indicator, in the form of a solution, are thymol blue, methyl red, bromothymol blue, and phenolphthalein. This mixture is important because each component loses or gains protons depending upon the acidity or alkalinity of the solution being tested. It is beneficial to use this type of universal ...
Higher levels of omega-6 fatty acids often found in ultraprocessed foods may interfere with the immune system’s fight against cancer cells, a new study says.
Phenol in the Berthelot reagent can be replaced by a variety of phenolic reagents, the most common being sodium salicylate, which is significantly less toxic. [1] This has been used for blood urea nitrogen (BUN) determinations and commonly is used to determine water and soil total and ammonia-N. Replacement of phenol by 2-phenylphenol reduces interferences by a variety of soil and water ...
Still, Americans’ emotional reactions as they look ahead to a second Trump term are mixed. Overall, slightly more people express a positive feeling (52%) than a negative one (48%), but the share ...