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Phenylhydrazine was the first hydrazine derivative characterized, reported by Hermann Emil Fischer in 1875. [7] [8] He prepared it by reduction of a phenyl diazonium salt using sulfite salts.
Usually, a "phenyl group" is synonymous with C 6 H 5 − and is represented by the symbol Ph (archaically, Φ), or Ø. Benzene is sometimes denoted as PhH. Phenyl groups are generally attached to other atoms or groups. For example, triphenylmethane (Ph 3 CH) has three phenyl groups attached to the same carbon center. Many or even most phenyl ...
A universal indicator is a pH indicator made of a solution of several compounds that exhibit various smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. A universal indicator can be in paper form or present in a form of a solution. [1]
Good sought to identify buffering compounds which met several criteria likely to be of value in biological research. pK a: Because most biological reactions take place near-neutral pH between 6 and 8, ideal buffers would have pK a values in this region to provide maximum buffering capacity there.
The pH level of food influences its flavor, texture, and shelf life. [33] Acidic foods, such as citrus fruits, tomatoes, and vinegar, typically have a pH below 4.6 [34] with sharp and tangy taste, while basic foods tastes bitter or soapy. [35] Maintaining the appropriate pH in foods is essential for preventing the growth of harmful ...
In and of themselves, pH indicators are usually weak acids or weak bases. The general reaction scheme of acidic pH indicators in aqueous solutions can be formulated as: HInd (aq) + H 2 O (l) ⇌ H 3 O + (aq) + Ind − (aq) where, "HInd" is the acidic form and "Ind −" is the conjugate base of the indicator. Vice versa for basic pH indicators ...
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Decrease in pH; When the pH decreases, the histidine residue is protonated and can no longer coordinate the metal tag, allowing the protein to be eluted. When nickel is used as the metal ion, it is eluted at around pH 4 and cobalt at around pH 6. Removal of metal ions