Nonmetals hydrogen halides

Nonmetals form covalent molecular hydrides, which consist of discrete molecules. These compounds are volatile and many are Bronstcd acids. Some are gases— for example, ammonia, the hydrogen halides (HF, HC1, HBr, HI), and the lighter hydrocarbons such as methane, ethane, ethene, and ethyne. Liquid molecular hydrides include water and hydrocarbons such as octane and benzene. 

In addition to functioning as Lewis acids, boron halides undergo many other types of reactions. As is typical of most compounds containing covalent bonds between a nonmetal and a halogen, the boron halides react vigorously with water to yield boric acid and the corresponding hydrogen halide. 

Nonmetal halides are generally hydrolyzed to a hydrogen halide and to an oxy-acid containing the other element. The first row nonmetal halides, eg, CC14, resist hydrolysis because the nonmetal element cannot expand its octet of electrons to form a bond to water before its bond to the halide is broken. Hydrolysis requires either an energetic water molecule to strike the halide or ionization of the covalent nonmetal—halide bond, processes that tend to be quite slow (16). 

In general, reactions such as these produce the hydrogen halide and an acid containing the nonmetal in the same oxidation state as the original halogen compound. One notable exception to this behavior is that of SF6 because it does not react with water (see Chapter 15). 

It is possible to prepare the hydrogen halides by direct combination of the elements, although this method is difficult to control (especially in the case of HF and HC1) or does not give rapid, efficient reaction (as with HI). A third method, the preferred one for HI, is the hydrolysis of covalent halogen compounds containing iodine bonded to a nonmetal ... 

Hydrogen reacts with nonmetals to form binary molecular hydrides. For example, H2 combines with the halogens to form colorless, gaseous hydrogen halides (Figure 6-5) ... 

In an aqueous reaction pattern typical of many nonmetal halides, each 5A halide reacts with water to yield the hydrogen halide and the oxoacid, in which E has the same oxidation number as it had in the original halide. For example, PX5 (O.N. of P = -E5) produces HX and phosphoric acid (O.N. of P = -E5) ... 

The halides of the elements have been surveyed throughout our tour of the representative elements. Common methods to prepare them include (1) direct reaction of the elements, (2) reactions of oxides or hydroxides with hydrogen halides, (3) reactions of oxides or lower halides with covalent fluorides, and (4) halogen exchange reactions. Nonmetal halides usually hydrolyze to form the corresponding hydroxide, oxide, or oxoacid. Pseudohalides are anions that resemble halides in their chemical behavior. 

PbR4-type compounds usually are not sensitive to air, insoluble in water, and very stable to hydrolysis. However, prolonged contact with air causes slow degradation, especially in the presence of light. They react readily with halogens, hydrogen halides, nonmetal halides, a series of salts (mainly metal halides), and with aqueous solutions of strong acids. They are much less sensitive to bases. 

An outstanding point which emerged from my early work on the interaction of hydroxy compounds and inorganic nonmetal halides, such as thionyl and phosphorus halides, was the vital function of the hydrogen halide formed in the reaction pattern. The interaction of hydrogen halides with alcohols, esters, and ethers has also operational importance. 

Lead dioxide Aluminum carbide, hydrogen peroxide, hydrogen sulfide, hydroxylamine, ni-troalkanes, nitrogen compounds, nonmetal halides, peroxoformic acid, phosphorus, phosphorus trichloride, potassium, sulfur, sulfur dioxide, sulfides, tungsten, zirconium... 

Nitric acid, fuming Organic matter, nonmetals, most metals, ammonia, chlorosulfonic acid, chromium trioxide, cyanides, dichromates, hydrazines, hydrides, HCN, HI, hydrogen sulflde, sulfur dioxide, sulfur halides, sulfuric acid, flammable liquids and gases... 

Reacts with many metals to give hydrogen, sometimes violently. With non-metals pyrophoric hydrides may result. Frequently initiates explosive reactions between other substances. Violent reactions with many non-metal and some metal halides and oxyhalides, also with many organometallic compounds. Many metal nonmetal-lides produce toxic, flammable or pyrophoric gases on contact with diprotium monoxide. 

A number of substances react vigorously with water, sometimes with the formation of hydrogen gas, which itself may ignite in the presence of air. Examples or such reactants are alkali metals, finely divided light metals and their hydrides, anhydrous metal oxides, anhydrous metal halides, nonmetal halides, and nonmetal oxides as well as certain organics such as anhydrides... 

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