Disappearing rainbow indicator
Encyclopedia
A Disappearing Rainbow Indicator is a pH indicator
that has different colors to indicate the range of the pH of the solution it is in. This is opposed to indicators like phenolphthalein
which have only two different colors and are able to indicate only whether the pH is above or below a certain point by using the various pH values of the indicators. It usually has the following composition:
Disappearing rainbow indicator is a flammable liquid. It is moderately toxic by inhalation or ingestion, and is an irritant.
The colors follow those of the visible spectrum
of light. The pH number is compared with the color. Anything below 7 is acidic (the lower the pH, the more acidic it is), 7 is neutral (neither acidic or alkali) & anything above 7 is alkali (the higher the pH, the more alkali
it is)
PH indicator
A pH indicator is a halochromic chemical compound that is added in small amounts to a solution so that the pH of the solution can be determined visually. Hence a pH indicator is a chemical detector for hydronium ions or hydrogen ions in the Arrhenius model. Normally, the indicator causes the...
that has different colors to indicate the range of the pH of the solution it is in. This is opposed to indicators like phenolphthalein
Phenolphthalein
Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Often used in titrations, it turns colorless in acidic solutions and pink in basic solutions...
which have only two different colors and are able to indicate only whether the pH is above or below a certain point by using the various pH values of the indicators. It usually has the following composition:
- Ethyl Alcohol
- PhenolphthaleinPhenolphthaleinPhenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Often used in titrations, it turns colorless in acidic solutions and pink in basic solutions...
- ThymolphthaleinThymolphthaleinThymolphthalein is an acid-base indicator. Its transition range is at approximately pH 9.3-10.5. Below this pH, it is colorless; above this pH, it is blue. The molar extinction coefficient for the blue thymolphthalein dianion is 38000 M-1cm-1 at 595 nm....
- p-Nitrophenol
Disappearing rainbow indicator is a flammable liquid. It is moderately toxic by inhalation or ingestion, and is an irritant.
Colors and meanings
- RedRedRed is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
- pHPHIn chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
1 - OrangeOrange (colour)The colour orange occurs between red and yellow in the visible spectrum at a wavelength of about 585–620 nm, and has a hue of 30° in HSV colour space. It is numerically halfway between red and yellow in a gamma-compressed RGB colour space, the expression of which is the RGB colour wheel. The...
- pH 2 - YellowYellowYellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...
- pH 3 - Pale greenGreenGreen is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
- pH 4 - Forest Green - pH 5
- Blue-green - pH 6
- BlueBlueBlue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
- pH 7
The colors follow those of the visible spectrum
Visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...
of light. The pH number is compared with the color. Anything below 7 is acidic (the lower the pH, the more acidic it is), 7 is neutral (neither acidic or alkali) & anything above 7 is alkali (the higher the pH, the more alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
it is)
More details
- Physical state: LiquidLiquidLiquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
- AppearanceVisual appearanceThe visual appearance of objects is given by the way in which they reflect and transmit light. The color of objects is determined by the parts of the spectrum of light that are reflected or transmitted without being absorbed...
: dark - Odour: alcohol-like
- pH value: Approximately 7
- Vapour Pressure: 25 mmHg (3.3 kPa)
- Vapour DensityDensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
: 1.3 kg/m³ - Boiling PointBoiling pointThe boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
: 80 °C - SolubilitySolubilitySolubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
: Soluble in waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
. - Specific gravitySpecific gravitySpecific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
/DensityDensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
: 0.93 g/cm³ - Molecular formula: MixtureMixtureIn chemistry, a mixture is a material system made up by two or more different substances which are mixed together but are not combined chemically...