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Phenolphthalein (/ f ɛ ˈ n ɒ l (f) θ ə l iː n / [citation needed] feh-NOL(F)-thə-leen) is a chemical compound with the formula C 20 H 14 O 4 and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations.
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 ...
Phenolphthalein can be synthesized by the condensation of phthalic anhydride with two equivalents of phenol under acidic conditions (hence the name). It was discovered in 1871 by Adolf von Baeyer. [8] [9] [10] Synthesis of phenolphthalein [11]
On November 29, 2000, the Philippine government's stake was sold to Delphi Holdings of Jose Alvarez for ₱3 billion payable within the next two years. [5] Alvarez who is said to be bidding in behalf of majority owner, the Nauru government, became the firm's chairman. Delphi Holdings paid the remaining ₱1 billion to the government in late ...
Chlorophenol red is an indicator dye that changes color from yellow to violet in the pH range 5.4 to 6.8. [2] The pH of a substance is determined by taking the negative logarithm of the Hydronium ion concentration and the indictor changes color due to the dissociation of H + ions. [3]
The economy saw continuous real GDP growth of at least 5% since 2012. The Philippine Stock Exchange index ended 2012 with 5,812.73 points a 32.95% growth from the 4,371.96-finish in 2011. [80] The Philippines achieved an investment grade rating for the first time in the first quarter of 2013.
The phthalide core is found a variety of more complex chemical compounds including dyes (such as phenolphthalein), fungicides (such as tetrachlorophthalide, often referred to simply as "phthalide"), and natural oils (such as butylphthalide).
Roberto Benedicto, Marcos' fraternity brother and associate, monopolized the Philippine sugar industry beginning in 1974, earning the name "Sugar King". [6] The international price of sugar steadily rose in the 1970s, which led to indiscriminate hoarding from the local market.