Search results
Results from the WOW.Com Content Network
In an aqueous solution, precipitation is the "sedimentation of a solid material (a precipitate) from a liquid solution". [1] [2] The solid formed is called the precipitate. [3] In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant. [4]
The solution needs to be near neutral, because silver hydroxide forms at high pH, while the chromate forms Ag 2 Cr 2 O 7 or AgHCrO4 at low pH, reducing the concentration of chromate ions, and delaying the formation of the precipitate. Carbonates and phosphates precipitate with silver, and need to be absent to prevent inaccurate results.
The stoichiometry of the reaction depends upon the concentration of nitric acid used. 3 Ag + 4 HNO 3 (cold and diluted) → 3 AgNO 3 + 2 H 2 O + NO Ag + 2 HNO 3 (hot and concentrated) → AgNO 3 + H 2 O + NO 2. The structure of silver nitrate has been examined by X-ray crystallography several times. In the common orthorhombic form stable at ...
The first representative of this class of reactions was the NaOH (outer electrolyte)+CuCl 2 (inner electrolyte). Later the NaOH+AgNO 3, the CuCl 2 +K 3 [Fe(CN) 6], the NaOH+AlCl 3, and the NH 3 +AgNO 3 reactions in several hydrogels have also proved to show similar behavior. Precipitate patterns forming in these reactions are exceptionally rich.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
Silver chloride is unusual in that, unlike most chloride salts, it has very low solubility. It is easily synthesized by metathesis: combining an aqueous solution of silver nitrate (which is soluble) with a soluble chloride salt, such as sodium chloride (which is used industrially as a method of producing AgCl), or cobalt(II) chloride.
If the substance lacks the ability to dissolve in water, the molecules form a precipitate. [3] When writing the equations of precipitation reactions, it is essential to determine the precipitate. To determine the precipitate, one must consult a chart of solubility. Soluble compounds are aqueous, while insoluble compounds are the precipitate.
They are present in total ionic equations to balance the charges of the ions. Whereas the Cu 2+ and CO 2− 3 ions combine to form a precipitate of solid CuCO 3. In reaction stoichiometry, spectator ions are removed from a complete ionic equation to form a net ionic equation. For the above example this yields: