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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 ...
The measurement of pH can become difficult at extremely acidic or alkaline conditions, such as below pH 2.5 (ca. 0.003 mol/dm 3 acid) or above pH 10.5 (above ca. 0.0003 mol/dm 3 alkaline). This is due to the breakdown of the Nernst equation in such conditions when using a glass electrode.
In both cases the phosphoric acid solution usually contains 23–33% P 2 O 5 (32–46% H 3 PO 4). It may be concentrated to produce commercial-or merchant-grade phosphoric acid, which contains about 54–62% P 2 O 5 (75–85% H 3 PO 4). Further removal of water yields superphosphoric acid with a P 2 O 5 concentration above 70% (corresponding to ...
The prevailing view in the 1940s and 1950s was that P availability was maximized near neutrality (soil pH 6.5–7.5), and decreased at higher and lower pH. [29] [30] Interactions of phosphorus with pH in the moderately to slightly acidic range (pH 5.5–6.5) are, however, far more complex than is suggested by this view. Laboratory tests ...
NaOCH 3 + HOC 6 H 5 → NaOC 6 H 5 + HOCH 3. Sodium phenoxide can also be produced by the "alkaline fusion" of benzenesulfonic acid, whereby the sulfonate groups are displaced by hydroxide: C 6 H 5 SO 3 Na + 2 NaOH → C 6 H 5 OH + Na 2 SO 3. This route once was the principal industrial route to phenol. [citation needed]
The molecule consists of a nitrogen atom with two methyl substituents and one hydrogen.Dimethylamine is a weak base and the pKa of the ammonium CH 3-NH + 2-CH 3 is 10.73, a value above methylamine (10.64) and trimethylamine (9.79).
The key signatures associated with those pitches change accordingly: the key of G has one sharp, the key of D has 2 sharps, and so on. Proceeding counterclockwise from the top of the circle, the notes change by descending fifths and the key signatures change accordingly: the key of F has one flat, the key of B ♭ has 2 flats, and so on.
The oldest surviving written account of Popol Vuh (ms c. 1701 by Francisco Ximénez, O.P.). Popol Vuh (also Popul Vuh or Pop Vuj) [1] [2] is a text recounting the mythology and history of the Kʼicheʼ people of Guatemala, one of the Maya peoples who also inhabit the Mexican states of Chiapas, Campeche, Yucatan and Quintana Roo, as well as areas of Belize, Honduras and El Salvador.