Barking dog reaction
Encyclopedia
The "Barking Dog" is an exothermic
chemical reaction
that results from the ignition of a mixture of carbon disulfide
and nitric oxide
.
It has been known for centuries; in 1853, Justus von Liebig
was using the bright blue flash and the distinctive ‘woof’ sound of the demonstration to enthrall his students.
In simple terms, the ‘Barking Dog’ reaction is a combustion
process, in which a fuel (carbon disulfide
, CS2) reacts with an oxidiser (nitric oxide
(NO) or nitrous oxide
(N2O)), producing heat and elemental sulfur
. The flame front in the reaction is a zone of very hot, luminous gas, produced by the reactants decomposing.
3 NO + CS2 -> 3/2 N2 + CO + SO2 + 1/8 S8
4 NO + CS2 -> 2 N2 + CO2 + SO2 + 1/8 S8
Exothermic
In thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...
chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
that results from the ignition of a mixture of carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...
and nitric oxide
Nitric oxide
Nitric oxide, also known as nitrogen monoxide, is a diatomic molecule with chemical formula NO. It is a free radical and is an important intermediate in the chemical industry...
.
It has been known for centuries; in 1853, Justus von Liebig
Justus von Liebig
Justus von Liebig was a German chemist who made major contributions to agricultural and biological chemistry, and worked on the organization of organic chemistry. As a professor, he devised the modern laboratory-oriented teaching method, and for such innovations, he is regarded as one of the...
was using the bright blue flash and the distinctive ‘woof’ sound of the demonstration to enthrall his students.
In simple terms, the ‘Barking Dog’ reaction is a combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
process, in which a fuel (carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...
, CS2) reacts with an oxidiser (nitric oxide
Nitric oxide
Nitric oxide, also known as nitrogen monoxide, is a diatomic molecule with chemical formula NO. It is a free radical and is an important intermediate in the chemical industry...
(NO) or nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...
(N2O)), producing heat and elemental sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
. The flame front in the reaction is a zone of very hot, luminous gas, produced by the reactants decomposing.
3 NO + CS2 -> 3/2 N2 + CO + SO2 + 1/8 S8
4 NO + CS2 -> 2 N2 + CO2 + SO2 + 1/8 S8