Search results
Results from the WOW.Com Content Network
Vanadium(III) oxide is the inorganic compound with the formula V 2 O 3.It is a black solid prepared by reduction of V 2 O 5 with hydrogen or carbon monoxide. [3] [4] It is a basic oxide dissolving in acids to give solutions of vanadium (III) complexes. [4]
In strongly acidic solutions, pH < 2, [VO 2 (H 2 O) 4] + is the predominant species, while the oxide V 2 O 5 precipitates from solution at high concentrations. The oxide is formally the acid anhydride of vanadic acid. The structures of many vanadate compounds have been determined by X-ray crystallography.
If acid is slowly added to a solution of Na 3 VO 4, the colour gradually deepens through orange to red before brown hydrated V 2 O 5 precipitates around pH 2. These solutions contain mainly the ions HVO 4 2− and V 2 O 7 4− between pH 9 and pH 13, but below pH 9 more exotic species such as V 4 O 12 4− and HV 10 O 28 5− ( decavanadate ...
An acidic oxide is an oxide that either produces an acidic solution upon addition to water, or acts as an acceptor of hydroxide ions effectively functioning as a Lewis acid. [1] Acidic oxides will typically have a low pK a and may be inorganic or organic .
A basic oxide, also called a base anhydride (meaning "base without water"), is usually formed in the reaction of oxygen with metals, especially alkali (group 1) and alkaline earth (group 2) metals. Both of these groups form ionic oxides that dissolve in water to form basic solutions of the corresponding metal hydroxide: Alkali metals (Group 1)
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula . For example, a solution of table salt , also known as sodium chloride (NaCl), in water would be represented as Na + (aq) + Cl − (aq) .
The cationic metal centres act as Lewis acid sites while the anionic oxygen centres act as Lewis bases. Surface hydroxyl groups can serve as Brønsted acid or base sites as they can give up or accept a proton. [14] The surface of most metal oxides will be, to some extent, hydroxylated under normal conditions when water vapor is present. [15]
In chemistry, the oxygen reduction reaction refers to the reduction half reaction whereby O 2 is reduced to water or hydrogen peroxide. In fuel cells, the reduction to water is preferred because the current is higher. The oxygen reduction reaction is well demonstrated and highly efficient in nature. [1] [2]