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Dissolved oxygen (D.O.) is widely used in water quality studies and routine operation of water reclamation facilities to analyze its level of oxygen saturation. In the test, an excess of manganese(II) salt, iodide (I −) and hydroxide (OH −) ions are added to a water sample causing a white precipitate of Mn(OH) 2 to form.
A simple nitrite test can be performed by adding 4 M sulfuric acid to the sample until acidic, and then adding 0.1 M iron(II) sulfate to the solution. A positive test for nitrite is indicated by a dark brown solution, arising from the iron-nitric oxide complex ion.
This is a common laboratory test to determine if sulfate anions are present. The sulfate ion can act as a ligand attaching either by one oxygen (monodentate) or by two oxygens as either a chelate or a bridge. [7] An example is the complex Co 2 (SO 4)] + Br − [7] or the neutral metal complex PtSO 4 (PPh 3) 2] where the sulfate ion is acting as ...
A common nitrate test, known as the brown ring test [2] can be performed by adding iron(II) sulfate to a solution of a nitrate, then slowly adding concentrated sulfuric acid such that the acid forms a layer below the aqueous solution. A brown ring will form at the junction of the two layers, indicating the presence of the nitrate ion. [3]
When measuring water treated with water softeners, high levels of total dissolved solids do not correlate to hard water, as water softeners do not reduce TDS; rather, they replace magnesium and calcium ions, which cause hard water, with an equal charge of sodium or potassium ions, e.g. Ca 2+ ⇌ 2 Na +, leaving overall TDS unchanged [9] or even ...
Ammonium ion concentration in the acid solution, and thus the amount of nitrogen in the sample, is measured via titration. If boric acid (or some other weak acid) was used, direct acid–base titration is done with a strong acid of known concentration. HCl or H 2 SO 4 can be used.
Sodium sulfate is a typical electrostatically bonded ionic sulfate. The existence of free sulfate ions in solution is indicated by the easy formation of insoluble sulfates when these solutions are treated with Ba 2+ or Pb 2+ salts: Na 2 SO 4 + BaCl 2 → 2 NaCl + BaSO 4. Sodium sulfate is unreactive toward most oxidizing or reducing agents.
This includes ions which form sulfides that are insoluble at high concentrations. The reagents used are H 2 S in the presence of NH 4 OH. NH 4 OH is used to increase the concentration of the sulfide ion, by the common ion effect - hydroxide ions from NH 4 OH combine with H + ions from H 2 S, which shifts the equilibrium in favor of the ionized ...