SUMMARY / RELATED TOPICS

Hydrogen chloride

The compound hydrogen chloride has the chemical formula HCl and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is commonly given the formula HCl. Hydrogen chloride is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a polar covalent bond; the chlorine atom is much more electronegative than the hydrogen atom. The molecule has a large dipole moment with a negative partial charge at the chlorine atom and a positive partial charge at the hydrogen atom. In part because of its high polarity, HCl is soluble in water. Upon contact, H2O and HCl combine to form hydronium cations H3O+ and chloride anions Cl− through a reversible chemical reaction: HCl + H2O → H3O+ + Cl−The resulting solution is called hydrochloric acid and is a strong acid.

The acid dissociation or ionization constant, Ka, is large, which means HCl dissociates or ionizes completely in water. In the absence of water, hydrogen chloride can still act as an acid. For example, hydrogen chloride can dissolve in certain other solvents such as methanol and protonate molecules or ions, can serve as an acid-catalyst for chemical reactions where anhydrous conditions are desired. HCl + CH3OH → CH3O+H2 + Cl−Because of its acidic nature, hydrogen chloride is a corrosive substance in the presence of moisture. Frozen HCl undergoes phase transition at 98.4 K. X-ray powder diffraction of the frozen material shows that the material changes from an orthorhombic structure to a cubic one during this transition. In both structures the chlorine atoms are in a face-centered array. However, the hydrogen atoms could not be located. Analysis of spectroscopic and dielectric data, determination of the structure of DCl indicates that HCl forms zigzag chains in the solid, as does HF; the infrared spectrum of gaseous hydrogen chloride, shown on the left, consists of a number of sharp absorption lines grouped around 2886 cm−1.

At room temperature all molecules are in the ground vibrational state v = 0. Including anharmonicity the vibrational energy can be written as. E v i b = h ν e ⋅ + h x e ν e ⋅ 2 To promote an HCl molecule from the v = 0 to the v = 1 state, we would expect to see an infrared absorption about νo = νe + 2xeνe = 2880 cm−1. However, this absorption corresponding to the Q-branch is not observed due to it being forbidden by symmetry. Instead, two sets of signals are seen owing to a simultaneous change in the rotational state of the molecules; because of quantum mechanical selection rules, only certain rotational transitions are permitted. The states are characterized by the rotational quantum number J = 0, 1, 2, 3... selection rules state that ΔJ is only able to take values of ±1. E r o t = h ⋅ B ⋅ J The value of the rotational constant B is much smaller than the vibrational one νo, such that a much smaller amount of energy is required to rotate the molecule. However, the vibrational energy of HCl molecule places its absorptions within the infrared region, allowing a spectrum showing the rovibrational transitions of this molecule to be collected using an infrared spectrometer with a gas cell.

The latter can be made of quartz as the HCl absorption lies in a window of transparency for this material. Abundant chlorine consists of two isotopes, 35Cl and 37Cl, in a ratio of 3:1. While the spring constants are identical within experimental error, the reduced masses are different causing measurable differences in the rotational energy, thus doublets are observed on close inspection of each absorption line, weighted in the same ratio of 3:1. Most hydrogen chloride produced on an industrial scale is used for hydrochloric acid production. In the chloralkali process, brine solution is electrolyzed producing chlorine, sodium hydroxide, hydrogen: 2 NaCl + 2 H2O → Cl2 + 2 NaOH + H2The pure chlorine gas can be combined with hydrogen to produce hydrogen chloride in the presence of UV light: Cl2 + H2 → 2 HClAs the reaction is exothermic, the installation is called an HCl oven or HCl burner; the resulting hydrogen chloride gas is absorbed in deionized water, resulting in chemically pure hydrochloric acid.

This reaction can give a pure product, e.g. for use in the food industry. The largest production of hydrochloric acid is integrated with the formation of chlorinated and fluorinated organic compounds, e.g. Teflon and other CFCs, as well as chloroacetic acid and PVC; this production of hydrochloric acid is integrated with captive use of it on-site. In the chemical reactions, hydrogen atoms on the hydr

Mikel Nieve

Mikel Nieve Iturralde is a Spanish professional road bicycle racer, who rides for UCI WorldTeam Mitchelton–Scott. Born in Leitza, Nieve won the sixteenth stage of the 2010 Vuelta a España, shaking off four riders to win solo in the mountain finish at the Alto de Cotobello, he earned another prestigious victory in the fifteenth stage of the 2011 Giro d'Italia, the queen stage of that year's edition, which Alberto Contador described as the most difficult stage of his life. Nieve had broken away early, crested the penultimate climb of the day, the Passo Fedaia, with only Stefano Garzelli in front of him. On the lower slope of the final climb to Gardeccia-Val di Fassa, Nieve passed Garzelli, held on to win the stage after having spent a little less than 7 hours and a half in the saddle, he finished 10th twice in the Giro d'Italia in 2011 and 2012. He finished 10th twice in the Vuelta a España in 2010 and 2011. In 2013, Nieve rode his first Tour de France, where he finished 3rd on Mont Ventoux and 9th on Alpe d'Huez.

He ended up finishing 12th overall. After the disbanding of the Euskaltel–Euskadi team was confirmed at the end of the 2013 season, Nieve agreed to join Team Sky on an initial two-year deal. In 2014, he won stage 8, the final stage of the Critérium du Dauphiné as well as finishing 8th overall. In 2015, Nieve finished 8th overall in the Vuelta a España, his highest Grand Tour finish to date. In 2016, Nieve won stage 13 of the Giro d'Italia, he went on to win the mountains classification. Nieve rode the Tour de France, where he helped Chris Froome take overall victory as one of his mountain domestiques. In August 2017, it was announced. Mikel Nieve profile at Team Sky Mikel Nieve at Cycling Archives Mikel Nieve profile at Cycling Base

Kajiya Line

The Kajiya Line was a railway line of West Japan Railway Company between Nishiwaki and Taka District all within Hyōgo Prefecture, Japan. The line closed on April 1, 1990. Notes 1: Nomura Station was renamed Nishiwakishi Station upon closure of the Kajiya Line. 2: The former town of Naka became a part of the town of Taka in 2005. The Banshū Railway opened the line between 1913 and 1923; the railway was acquired by the Bantan Railway in 1923 and nationalised in 1943 together with other Bantan Railway lines, i.e. the Kakogawa Line, the Takasago Line, the Miki Line, the Hōjō Line. Under the operation of Japanese National Railways, freight services ceased in 1974. JR West succeeded the line in 1987 and closed it in 1990, concurrently with the Miyazu Line and the Taisha Line, as the last of 83 "specified local lines" selected for closure; this article incorporates material from the corresponding article in the Japanese Wikipedia