Hydrides reaction with water

The sodium hydride reaction with water is pH limited and requires an additional reactant to force the reaction to completion. 

How do the following hydrides react with water NaH, CH4, SiH4 and HI Comment on these reactions in terms of the nature of the chemical bonds in these compounds. Suggest reasons for the increase in acidity in the series PH3, HjS, HCl. How would you seek to establish this order experimentally ... 

Potassium hydride (KH) is a source of the strongly basic hydride ion ( H ) Using curved arrows to track electron movement write an equation for the reaction of hydride ion with water What is the conjugate acid of hydride lon ... 

Calcium hydride is highly ionic and is insoluble in all common inert solvents. It can be handled in dry air at low temperatures without difficulty. When heated to about 500°C, it reacts with air to form both calcium oxide and nitride. Calcium hydride reacts vigorously with water in either Hquid or vapor states at room temperature. The reaction with water provides 1.06 Hters of hydrogen per gram CaH2. 

Quahtative insight can, however, be obtained by focusing on the reactions with water, the extent and vigor of which can vary widely. In general, however, hydrides react exothermically with water, resulting in the generation of hydrogen. 

The corrosion behavior of plutonium metal has been summarized (60,61). a-Plutonium oxidizes very slowly in dry air, typically <10 mm/yr. The rate is accelerated by water vapor. Thus, a bright metal surface tarnishes rapidly in normal environments and a powdery surface soon forms. Eventually green PUO2 [12059-95-9] covers the surface. Plutonium is similar to uranium with respect to corrosion characteristics. The stabilization of 5-Pu confers substantial corrosion resistance to Pu in the same way that stabilization of y-U yields a more corrosion-resistant metal. The reaction of Pu metal with Hquid water produces both oxides and oxide-hydrides (62). The reaction with water vapor above 100°C also produces oxides and hydride (63). 

Reactions with water are complicated and are affected by the presence of oxygen. With boiling water or steam, oxide is formed on the surface of the metal and H2 is liberated. Since the metals react readily with the latter, hydrides are produced which themselves react rapidly with... 

Reaction with water to yield a carboxylic acid Reaction with an alcohol to yield an ester Reaction with ammonia or an amine to yield an amide Reaction with a hydride reducing agent to yield an aldehyde or an alcohol... 

Reaction of calcium hydride (CaHJ with water. 

Cobalt(II) complexes of three water-soluble porphyrins are catalysts for the controlled potential electrolytic reduction of H O to Hi in aqueous acid solution. The porphyrin complexes were either directly adsorbed on glassy carbon, or were deposited as films using a variety of methods. Reduction to [Co(Por) was followed by a nucleophilic reaction with water to give the hydride intermediate. Hydrogen production then occurs either by attack of H on Co(Por)H, or by a disproportionation reaction requiring two Co(Por)H units. Although the overall I easibility of this process was demonstrated, practical problems including the rate of electron transfer still need to be overcome. " " ... 

Aluminum is known to undergo another reaction with water, making the hydride ... 

The finely divided hydride produced by pyrolysis is pyrophoric in air, while synthesis from the elements produces a substantially air-stable product [1]. That prepared by reduction of butylmagnesium bromide with lithium tetrahydroalumi-nate is pyrophoric and reacts violently with water and other protic compounds [2], The hydride produced from magnesium anthracene has a very large specific surface area and is pyrophoric [3], In the context of use of the hydride for energy storage purposes, ignition and combustion behaviour of 100-400 g portions were studied, as well as the reaction with water [4],... 

Acid-base reactions also include those in which the solvent itself functions as an acid or base. This can be shown as follows. Sodium hydride reacts with water to produce a basic solution,... 

With hydrogen, the alkali metals form the mono-hydrides MeH, having salt-like properties and a partially ionic, Me H, NaCl-type structure. They are colourless crystalline solids having a fairly negative AH of formation. The mono-hydrides react with water. They may be prepared from hydrogen and the metal (heated at 700-800°C for Li, 350-400°C for the others) or through the reaction of hydrogen with the alkali mono-oxide, nitride, etc. 

Sodium hydride is a powerful reducing agent. It reduces metal oxides, metal chlorides, and a number of oxidizible substances. Its reactions with water can proceed with explosive violence ... 

When the absorption of the hydrogen stops (how can this be determined ), cool the apparatus to room temperature in a hydrogen atmosphere. Write the equation of the reaction. Extract the boat from the tube. What is the colour of the product See how lithium hydride reacts with water. What is the nature of the bond in a lithium hydride molecule ... 

Inorganic As(III) and As(V) were determined by atomic absorption spectrometry using the hydride technique. Total inorganic arsenic, As(III) + As(V), was measured after a prereduction reaction of As(V) to As(III) in acidic solution containing potassium iodide and ascorbic acid. For the selective hydride formation of As(III), samples were maintained at pH 5.0 during the hydride reaction (with 3% NaBH4, 1% NaOH) with a citrate-sodium hydroxide buffer solution (31). As(V) was determined by difference between total As and As(III). The detection limit of As(III) and As(V) was 0.1 nM. The selectivity of this method was checked by additions of As(III) and As(V) to lake water 95-100% recovery of As(III) and As(V) was found (32). 

Table 2 gives thermoehemica data of alkaline-earth metal hydrides. All form orthorhombic crystals. Calcium hydride is a convenient portable source of hydrogen gas, which results from its reaction with water. 

Calcium hydride is used as a portable source of hydrogen because of its reaction with water ... 

The carbonyl may be displaced by chloride to form m-[PtCl2(PR3)2]> or by reaction with water to form the /rrtKS-hydride (43). 

The triphenylphosphine cation reacts with alcohols to form an alkoxy-carbonyl which yields the hydride on reaction with water. 

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