Phenolphthalein

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Phenolphthalein

Phenolphthalein is a chemical compound

Chemical compound

A chemical compound is a Chemical substance consisting of two or more different chemical element Chemical bond together in a fixed mass ratio that can be split into simpler substances....
with the formula

Chemical formula

A chemical formula is a way of expressing information about the atoms that constitute a particular chemical compound, and how the relationship between those atoms changes in chemical reactions....
C

Carbon

Carbon is a chemical element with chemical symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalence?making four electrons available to form covalent bond chemical bonds....
₂₀H

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the chemical symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly combustion and explosive Diatomic molecule gas with the molecular formula H2....
₁₄O

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
₄ (often written as "HIn" or "phph" in shorthand notation). Often used in titration

Titration

Titration is a common laboratory method of quantitative Analytical chemistry that is used to determine the unknown concentration of a known reactant....
s, it turns colorless in acid

Acid

An acid is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion Activity greater than in pure water, i.e....
ic solutions and pink in basic

Base (chemistry)

In chemistry, a base is most commonly thought of as an aqueous substance that can accept protons. A base is also often referred to as an alkali if OH- ions are involved....
solutions. If the concentration of indicator is particularly strong, it can appear purple.

In strongly basic solutions, phenolphthalein's pink color undergoes a rather slow fading reaction and becomes colorless again.

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Encyclopedia

Phenolphthalein is a chemical compound

Chemical compound

Chemical formula

Carbon

Hydrogen

Oxygen

Titration

Titration is a common laboratory method of quantitative Analytical chemistry that is used to determine the unknown concentration of a known reactant....
s, it turns colorless in acid

Acid

Base (chemistry)

Species	In	H₂In	In^2-	In(OH)^3-
Structure
Model
pH	< 0	0-8.2	8.2-12.0	>12.0
Conditions	strongly acidic	acidic or near-neutral	basic	strongly basic
Color	orange	colorless	pink to fuchsia Fuchsia (color) Fuchsia is a purple color named after the flower of the fuchsia plant. Fuchsia is used as an alias for electric magenta.There is also a somewhat redder and slightly less saturated hue termed fashion fuchsia that is used in women's fashion ....	colorless
Image

The rather slow fading reaction that produces the colorless InOH^3- ion is sometimes used in classes for the study of reaction kinetics.

Phenolphthalein is insoluble in water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
, and is usually dissolved in alcohol

Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
s for use in experiment

Experiment

In scientific inquiry, an experiment is a method of investigating causal relationships among variables. An experiment is a cornerstone of the empiricism approach to acquiring data about the world and is used in both natural sciences and social sciences....
s. It is itself a weak acid, which can lose H⁺ ions in solution. The phenolphthalein molecule is colorless. However, the phenolphthalein ion is pink. When a base is added to the phenolphthalein, the molecule ions equilibrium shifts to the right, leading to more ionization as H⁺ ions are removed. This is predicted by Le Chatelier's principle

Le Châtelier's principle

In chemistry, Le Chatelier's Principle, also called the Le Chatelier-Braun principle, can be used to predict the effect of a change in conditions on a chemical equilibrium....
.

Synthesis

Phenolphthalein is synthesized by condensation of phthalic anhydride

Phthalic anhydride

Phthalic anhydride is the organic compound with the chemical formula C6H42O. This anhydride of phthalic acid, a colourless solid, is an important industrial chemical, especially for the large-scale production of plasticizers for plastics....
with two equivalents of phenol

Phenol

Phenol, also known as carbolic acid, is a toxic, white crystalline solid with a sweet tarry odor, commonly referred to as a "hospital smell"....
under acidic conditions (hence the name). It was discovered in 1871 by Adolf von Baeyer

Adolf von Baeyer

Johann Friedrich Wilhelm Adolf von Baeyer was a Germany chemistry who synthesized indigo dye, and was the 1905 recipient of the Nobel Prize in Chemistry....
.

Uses

Phenolphthalein (pH indicator PH indicator A pH indicator is a halochromism chemical chemical compound that is added in small amounts to a solution so that the pH of the solution can be determined easily.... )
below pH 8.2		above pH 10.0
colorless		fuchsia Fuchsia (color) Fuchsia is a purple color named after the flower of the fuchsia plant. Fuchsia is used as an alias for electric magenta.There is also a somewhat redder and slightly less saturated hue termed fashion fuchsia that is used in women's fashion ....

Phenolphthalein has been used for over a century as a laxative

Laxative

Laxatives are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the Colon for rectum and bowel examinations, and may be supplemented by enemas in that circumstance....
, but is now being removed from the market because of concerns over carcinogen

Carcinogen

The term carcinogen refers to any substance, radionuclide or radiation that is an agent directly involved in the promotion of cancer or in the increase of its propagation....
icity. However, the small amounts usually used in experiments are harmless.

Phenolphthalein is used to perform a presumptive blood test, and is commonly known as the Kastle-Meyer test

Kastle-Meyer test

The Kastle-Meyer test is a forensic Presumptive test blood test, first described in 1903, in which the chemical indicator phenolphthalein is used....
. A dry sample is collected with a swab or filter paper. First a few drops of alcohol, then a few drops of phenolphthalein and finally a few drops of hydrogen peroxide

Hydrogen peroxide

Hydrogen peroxide is a very pale blue liquid which appears colorless in a dilute solution, slightly more viscous than water. It is a weak acid....
are dripped onto the sample. If the sample turns pink then it is a positive test. This test is nondestructive to the sample; it can be kept and used in further tests at the lab. This test has the same reaction with blood from any animal, so further testing would be required to determine whether it originates from a human.

Phenolphthalein is used in toys, for example as a component of disappearing inks, or disappearing dye on the Hollywood Hair Barbie

Barbie

Barbie is a fashion doll manufactured by Mattel and launched in March 1959. USA businesswoman Ruth Handler is credited with the creation of the doll using a Germany doll called Bild Lilli doll as her inspiration....
hair. In the ink it is mixed with sodium hydroxide

Sodium hydroxide

Sodium hydroxide , also known as lye, caustic soda and sodium hydrate, is a caustic metallic Base . Sodium hydroxide forms a strong alkaline solution when dissolved in a solvent such as water, however, only the hydroxide ion is basic....
, which reacts with carbon dioxide in the air. This reaction leads to the pH falling below the color change threshold as hydrogen ions are released via the reaction:

OH^-

Hydroxide

In chemistry, hydroxide is the name for the Diatomic molecule anion OH-, consisting of oxygen and hydrogen atoms, usually derived from the Dissociation of a base ....
(aq) + CO₂

Carbon dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalent bond to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state....
(g) ? CO₃^2-

Carbonate

In chemistry, a carbonate is a salt or ester of carbonic acid....
(aq) + H⁺

Proton

The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+....
(aq)

To develop the hair and "magic" graphical patterns, the ink is sprayed with a solution of hydroxide, which leads to the appearance of the hidden graphics by the same mechanism described above for color change in alkaline solution. The pattern will eventually disappear by the same reaction with carbon dioxide

Carbon dioxide

Thymolphthalein

Thymolphthalein is an acid-base PH indicator. Its transition range is at approximately pH 9.3-10.5. Below this pH, it is colorless; above this pH, it is blue....
is used for the same purpose and in the same way, when blue color is desired.

Phenolphthalein is used as an acid or base indicator where in contact or presence of acid it will turn colorless and with base, it will turn into a pinkish violet color. It is also a component in universal indicator

Universal indicator

Universal indicator is a pH indicator that transitions through numbers 3-12 to indicate the acidity or alkalinity of solutions. Although there are a number of commercially available universal pH indicators, most are a variation of a formula patented by Yamada in 1923....
, a solution consisting of a mixture of pH indicators (usually phenolphthalein, methyl red

Methyl red

Methyl red, also called C.I. Acid Red 2, is an PH indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder....
, bromothymol blue

Bromothymol blue

Bromothymol blue is a chemical pH indicator for weak acids and Base . The chemical is also used for observing Photosynthesis activities or respiratory indicators ....
, and thymol blue

Thymol blue

Thymol blue is a brownish-green or reddish-brown crystaline powder that is used as an pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions....
).

It is also used to test for signs of carbonation reactions in concrete. If the concrete is alkali, the concrete has not reacted.

Phenolphthalein

Synthesis

Uses

See also

External links