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for preparing 0.1 normal solution of potassium permanganate you have to disssolve 3.16 g potssium permangnate in 1L water bt in alkaline or neutral medium reactions of potassium permanganate is different and Mn gains 3 electrons in redox reaction,so far alkaline medium redox titration equivalent wt of KMnO4 will be 158\3=52.6.so far,0.1 N KMnO4 in alkaline medium redox titration dissolve 5.26 g in 1L sol.
This is far to be a rule for this titration.
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Redox Titration refers to some titration based on the redox reaction between the titrant and analyte.
It is used as indicator for the endpoint of a Iodometric (redox) titration: it gives a bluish grey to black color with very minute excess of Iodine-iodide ions (I3-)
Acid base titration involves neutralization reaction between an acid and a base. whereas redox titration involves redox reaction between an oxidizing agent and reducing agent.
No
i dontknow
types of conductometric titration: acid base titration complexometric titration replacement titration redox titration precipitation titration
A thiosulfate titration is mostly carried out to determine the amount of iodine present in the solution. In these reactions, thiosulfate ion acts as the reducing agent. This types titrations are often called as 'iodometric titrations'.
N (normality) describes a solution that contains 1 gram equivalent weight (gEW) per liter solution. An equivalent weight is equal to the molecular weight divided by the valence (here it gets a little tricky, for acids ands bases it refers to the number of H+ or OH-, in salts it must be expressed which ion is meant unless the ratio is 1:1). In the case of KMnO4, equivalent wt is reaction specific. When KMnO4 is used in acid medium as oxidiser, 5 electrons are gained by Mn atom. So equivalent wt of KMnO4 in acid medium = Molecular wt/no.of electrons gained in redox reaction = 158/5 =31.6. So for 0.1N KMnO4 solution, you have to dissolve 3.16g KMnO4 in 1L water. (Usually a little bit excess is taken, say 3.25g, since some crystals of KMnO4 will be remained undissolved that have to be removed by filtration. So eventhough u r preparing 0.1N KMnO4 solution by accurate weighing,it is not a primary standard and u have to standardise it against a primary std such as oxalic acid or sodium oxalate. In alkaline or neutral medium, reaction of KMnO4 is different and Mn gains 3 electrons in redox reaction. So, for alkaline medium redox titrations, equivalent wt of KMnO4 will be 158/3 = 52.6. So for 0.1N KMnO4 solution in alkaline medium redox titration, dissolve 5.26g in 1L water.
For preparation of standard solution of Mohr salt {FeSO4.(NH4)2SO4.6H2O}, it's necessary to add dilute H2SO4 to prevent the Fe2+ ions of Mohr salt solution from undergoing oxidation (to Fe3+). Just try to prepare the standard solution without adding this acid. You'll observe that your "Mohr solution" will become yellow in colour, i.e., it won't remain "Mohr salt solution" anymore, hence can't be used in titration. And while doing the titration of the Mohr salt solution with KMnO4 (or even with K2Cr2O7), you need to add dilute H2SO4. The reason is well explained by the chemical equation involved: reduction: (MnO4)- + 8H+ + 5e ----> Mn2+ + 4H2O oxidation: Fe2+ ----> Fe3+ + e net equation: (MnO4)- + 8H+ + 5Fe2+ ----> Mn2+ + 4H2O + 5Fe3+ There is involvement of H+ ions in this reaction. This redox titration requires acidic medium. Moreover, KMnO4 acts as a very good oxidizing agent in the presence of acidic medium, than in the basic and neutral medium. NOTE: Now a query may arise that for providing acidic medium, can HCl or HNO3 be used? (Let me tell you it's one of the favourite questions of external examiners) The answer is NO, because HNO3 is a very strong oxidizing agent. So, the Fe2+ present will be oxidized both by KMnO4 and HNO3, which will result in an error in determination of volume of KMnO4 reacting with Mohr salt solution. Also, HCl can't be used because Cl- from HCl will be oxidized by KMnO4: HCl (aq) ---> H+ (aq) +Cl- (aq) oxidation by KMnO4=> 2Cl- ----> Cl2 + 2e So, some extra KMnO4 will be used up because it will oxidize both- Cl- as well as Fe2+, => error in titration.