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The oxidation number for BaSO4 is 6. It goes as follows: +2 for Ba +6 for S -2 for O
2 S2O32- + I2 --> S4O62- + 2 I-thiosulfate + iodine -> tetrathionate* + iodide* -O3=-=S-S-S-S=-=O3-
The number represents the charge on the ion. The number is the quantity of electrons lost or gained by the elemental atom to become an ion. Thus gaining 1 electron makes the ion -1, because the electron is negatively charged. Losing an electron results in a positively charged ion +1. So if two electrons are gained the charge is -2. These numbers are also called oxidation numbers, representing the oxidation state of the element as the ion.
(1) io3- + 5i- + 6h+ ® 3i2 + 3h2o (2) i2 + 2s2o32- ® 2i- + s4o62-
The only known and possible reaction is the following redox (reduction-oxidation) reaction between I3- (Iodine-Iodide complex) and S2O32- (thiosulfate)I3- + 2 S2O32- --> 3 I- + S4O62-ox. + red.So the reaction between potassium iodide (KI) and potassium thiosulfate (K2S2O3) is NOT possible because they both are reductors (electron donors).Iodine-Iodide complex is essentially Iodine is an oxidator, bound to a non-reacting I- ion (Iodide)
The oxidation number for BaSO4 is 6. It goes as follows: +2 for Ba +6 for S -2 for O
2 S2O32- + I2 --> S4O62- + 2 I-thiosulfate + iodine -> tetrathionate* + iodide* -O3=-=S-S-S-S=-=O3-
With 'sodium thiosulfate' (two words!) and bromine the reaction will be strong to give oxidised tetrathionate and reduced bromide: 2 S2O32−(aq) + Br2(aq) → S4O62−(aq) + 2 Br−(aq)
s2o32-to give s4o62-
The number represents the charge on the ion. The number is the quantity of electrons lost or gained by the elemental atom to become an ion. Thus gaining 1 electron makes the ion -1, because the electron is negatively charged. Losing an electron results in a positively charged ion +1. So if two electrons are gained the charge is -2. These numbers are also called oxidation numbers, representing the oxidation state of the element as the ion.
boring stuff
(1) io3- + 5i- + 6h+ ® 3i2 + 3h2o (2) i2 + 2s2o32- ® 2i- + s4o62-
The only known and possible reaction is the following redox (reduction-oxidation) reaction between I3- (Iodine-Iodide complex) and S2O32- (thiosulfate)I3- + 2 S2O32- --> 3 I- + S4O62-ox. + red.So the reaction between potassium iodide (KI) and potassium thiosulfate (K2S2O3) is NOT possible because they both are reductors (electron donors).Iodine-Iodide complex is essentially Iodine is an oxidator, bound to a non-reacting I- ion (Iodide)
Add some mildly acid Iodide to the hypo chlorite solution.Titrate the formed Iodine-Iodide complex (I3-) with disodium thiosulfate until the starch (added at almost the end) color (black-blue with Iodine-Iodide complex) is disappeared.ClO- + Cl- + 2 H+ --> 'Cl2'available + H2O'Cl2'available + 3 I- --> 2 Cl- + I3-I3- + 2 S2O32- --> 3 I- + S4O62-(There are official -standard- Analytical Methods and Testing Procedures available on this subject).
Thiosulfate: 2 S2O32- --> S4O62- + 2e-equivalency to:Chlorine: 1 Cl2 + 2e- --> 2Cl-31.6 ml * 0.141 mmol/ml S2O32- = 4.456 mmol S2O32-= 4.456 *(2 electron / 2 S2O32-) = 4.456 mmol (electrons) == 4.456 *(1 Cl2 / 2 electron) = 2.228 mmol Cl2 == 2.228 * 70.90 mg/mmol Cl2 = 158 mg == 0.158 g Chlorine
In iodometric titrations sodium thiosulfate is the titrant whereas the KI will reduce the analyte; eg: Cu2+ to Cu+. The I2 produced is then titrated by the sodium thiosulphate. Cu2+ + I- --> CuI + I3- I3- + 2 S2O32- ¾® 3 I- + S4O62- To answer your question: KI (reducing agent) is added to generate the iodine by the reduction of the analyte (Cu2+) The formed iodine is then back-titrated with thiosulfate (titrant) to determine the amount of analyte originally present. As you can see the KI and sodium thiosulfate serve two different purposes. KI improves solubility of Iodine
The large diversity of chemical reactions and approaches to their study results in the existence of several concurring, often overlapping, ways of classifying them. Below are examples of widely used terms for describing common kinds of reactions.Isomerisation, in which a chemical compound undergoes a structural rearrangement without any change in its net atomic composition; see stereoisomerismDirect combination or synthesis, in which 2 or more chemical elements or compounds unite to form a more complex product:N2 + 3 H2 → 2 NH3 Chemical decomposition or analysis, in which a compound is decomposed into smaller compounds or elements:2 H2O → 2 H2 + O2 Single displacement or substitution, characterized by an element being displaced out of a compound by a more reactive element:2 Na(s) + 2 HCl(aq) → 2 NaCl(aq) + H2(g) Metathesis or Double displacement reaction, in which two compounds exchange ions or bonds to form different compounds:NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s) Acid-base reactions, broadly characterized as reactions between an acid and a base, can have different definitions depending on the acid-base concept employed. Some of the most common are: Arrhenius definition: Acids dissociate in water releasing H3O+ ions; bases dissociate in water releasing OH- ions.Brønsted-Lowry definition: Acids are proton (H+) donors; bases are proton acceptors. Includes the Arrhenius definition.Lewis definition: Acids are electron-pair acceptors; bases are electron-pair donors. Includes the Brønsted-Lowry definition.Redox reactions, in which changes in oxidation numbers of atoms in involved species occur. Those reactions can often be interpreted as transferences of electrons between different molecular sites or species. An example of a redox reaction is:2 S2O32−(aq) + I2(aq) → S4O62−(aq) + 2 I−(aq) In which I2 is reduced to I- and S2O32- (thiosulfate anion) is oxidized to S4O62-. Combustion, a kind of redox reaction in which any combustible substance combines with an oxidizing element, usually oxygen, to generate heat and form oxidized products. The term combustion is usually used for only large-scale oxidation of whole molecules, i.e. a controlled oxidation of a single functional group is not combustion.C10H8+ 12 O2 → 10 CO2 + 4 H2O CH2S + 6 F2 → CF4 + 2 HF + SF6 Disproportionation with one reactant forming two distinct products varying in oxidation state.2 Sn2+ → Sn + Sn4+ Organic reactions encompass a wide assortment of reactions involving compounds which have carbon as the main element in their molecular structure. The reactions in which an organic compound may take part are largely defined by its functional groups.