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]
Dissolution of vanadium pentoxide in strongly basic aqueous solution gives the colourless VO 3− 4 ion. On acidification, this solution's colour gradually darkens through orange to red at around pH 7. Brown hydrated V2O5 precipitates around pH 2, redissolving to form a light yellow solution containing the [VO 2 (H 2 O) 4] + ion. The number and ...
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 ...
Vanadic acid, H 3 VO 4 exists only at very low concentrations because protonation of the tetrahedral species [H 2 VO 4] − results in the preferential formation of the octahedral [VO 2 (H 2 O) 4] + species. 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 ...
At 25 °C (77 °F), solutions of which the pH is less than 7 are acidic, and solutions of which the pH is greater than 7 are basic. Solutions with a pH of 7 at 25 °C are neutral (i.e. have the same concentration of H + ions as OH − ions, i.e. the same as pure water). The neutral value of the pH depends on the temperature and is lower than 7 ...
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)
Acidic oxides will typically have a low pK a and may be inorganic or organic. A commonly encountered acidic oxide, carbon dioxide produces an acidic solution (and the generation of carbonic acid) when dissolved. Generally non-metallic oxides are acidic. [2] The acidity of an oxide can be reasonably assumed by its accompanying constituents.
Another possibility is the molecular autoionization reaction between two water molecules, in which one water molecule acts as an acid and another as a base. H 2 O + H 2 O ⇌ H 3 O + + HO −. The bicarbonate ion, HCO − 3, is amphoteric as it can act as either an acid or a base: As an acid, losing a proton: HCO − 3 + OH − ⇌ CO 2− 3 ...