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Redox titrations with KMnO4 and K2Cr2O7

37 questions on Redox titrations with KMnO4 and K2Cr2O7 from the Equivalent Concept and Titration chapter: 7 NEET level, 15 JEE Main, 15 JEE Advanced. Each one opens with its answer and solution.

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The equivalent mass of KMnO4 (molar mass 158 g mol^-1) acting as an oxidant in acidic medium is NEET level
The equivalent mass of K2Cr2O7 (molar mass 294 g mol^-1) as an oxidant in acidic medium, where Cr2O7^2- changes to Cr^3+, is NEET level
Which acid is normally used to acidify the solution in a titration of Fe^2+ against KMnO4? NEET level
Acidified 0.020 M KMnO4 is used to oxidise 0.10 mol of FeSO4 to Fe^3+. The volume of permanganate solution required is NEET level
20.0 mL of an oxalic acid solution needs 22.4 mL of 0.0200 M KMnO4 in hot dilute H2SO4 (H2C2O4 oxidised to CO2). The molarity of the oxalic acid is JEE Main level
A 1.40 g sample containing FeSO4 (molar mass 152 g mol^-1) as the only oxidisable substance is dissolved in dilute acid and requires 25.0 mL of 0.0400 M KMnO4. ... JEE Main level
In acidic KMnO4 titrations, the number of moles of KMnO4 needed for 1 mol of FeC2O4 : 1 mol of FeSO4 : 1 mol of H2C2O4 respectively is in the ratio JEE Main level
Which of the following statements about the titration of Fe^2+ with acidified K2Cr2O7 are correct? JEE Main level
A 20.0 mL portion of an acidified FeSO4 solution required 28.4 mL of 0.0250 M K2Cr2O7 for complete oxidation of Fe^2+ to Fe^3+. Find the molarity of the FeSO4 s... JEE Main level
10.0 mL of a hydrogen peroxide solution is titrated in acidic medium with 0.0200 M KMnO4, requiring 18.4 mL (H2O2 is oxidised to O2). The molarity of H2O2 is JEE Main level
The same quantity of a reductant is oxidised separately by KMnO4 in strongly acidic, neutral and strongly alkaline (to MnO4^2-) media. The ratio of the moles of... JEE Main level
A 0.500 g sample containing Na2C2O4 (molar mass 134 g mol^-1) and inert matter requires 30.0 mL of 0.0200 M KMnO4 in hot acidic solution. Calculate the mass per... JEE Main level
Two 25.0 mL portions of a solution containing Fe^2+ and Fe^3+ are taken. The first needs 12.0 mL of 0.0200 M KMnO4 in acid. The second is first shaken with zinc... JEE Advanced level
A 100 mL solution contains oxalic acid (H2C2O4) and sodium oxalate (Na2C2O4). A 20.0 mL portion needs 24.0 mL of 0.100 M NaOH with phenolphthalein (only the fre... JEE Advanced level
A mixture contains 0.100 mol of FeC2O4 and 0.0500 mol of Fe2(C2O4)3. Assuming only Fe^2+ and oxalate are oxidised, the moles of KMnO4 required in acid are JEE Advanced level
A 0.500 g iron ore sample is dissolved and all iron is converted to Fe^2+, which needs 21.5 mL of 0.0200 M K2Cr2O7. Taking the molar mass of Fe2O3 as 160 g mol^... JEE Advanced level
Which of the following correctly give the moles of acidified KMnO4 needed per mole of the substance (each product is the highest stable oxidation state: oxalate... JEE Advanced level
A solution contains 0.0100 mol Fe^2+ and 0.0100 mol C2O4^2- (no other reductant). Which of the following are correct? JEE Advanced level
1.26 g of crystalline oxalic acid H2C2O4. x H2O is dissolved to make 250 mL of solution. A 25.0 mL portion requires 20.4 mL of 0.0200 M KMnO4 in hot acid. Using... JEE Advanced level
No external indicator is needed in the titration of Fe^2+ against acidified KMnO4 because: NEET level
Which acid is used to acidify the solution in titrations with KMnO4? NEET level
A suitable indicator for the titration of Fe^2+ against K2Cr2O7 in acidic medium is: NEET level
25.0 mL of a ferrous sulphate solution requires 21.5 mL of 0.0200 M KMnO4 in acidic medium. The molarity of the Fe^2+ solution is: JEE Main level
Volume of 0.100 M oxalic acid that reacts completely with 10.0 mL of 0.0500 M acidified KMnO4 is: JEE Main level
Using K=39, Cr=52, O=16 (molar mass of K2Cr2O7=294), the mass of K2Cr2O7 needed in acidic medium to oxidise 0.0240 mol of Fe^2+ to Fe^3+ is: JEE Main level
3.458 g of Mohr's salt (molar mass 392 g mol^-1) is dissolved in water and made up to 250.0 mL. A 25.0 mL portion is acidified and titrated with 0.0200 M KMnO4.... JEE Main level
A 0.4250 g sample containing sodium oxalate (Na2C2O4, molar mass 134) and inert matter is dissolved, acidified and titrated at 60-70 degC with 0.0200 M KMnO4; 2... JEE Main level
Which statements about permanganate titrations are correct? JEE Main level
Which statements about K2Cr2O7 as an oxidant in acidic medium are correct? JEE Main level
A mixture of 1.44 g of FeC2O4 (molar mass 144) and 1.52 g of FeSO4 (molar mass 152) is dissolved in dilute H2SO4 and titrated with 0.0200 M KMnO4, which oxidise... JEE Advanced level
25.0 mL of 0.0500 M K2Cr2O7 is acidified and treated with excess KI. The iodine liberated is titrated with 0.100 M Na2S2O3 (oxidised to S4O6^2-). The volume of ... JEE Advanced level
10.0 mL of a hydrogen peroxide solution is diluted to 100.0 mL. A 20.0 mL portion of the diluted solution needs 15.0 mL of 0.0200 M acidified KMnO4. The volume ... JEE Advanced level
0.6250 g of an iron ore is dissolved in acid and all the iron is reduced to Fe^2+ (excess reductant removed). The solution needs 28.4 mL of 0.0200 M K2Cr2O7. Ta... JEE Advanced level
0.4850 g of limestone is dissolved in acid and all calcium is precipitated as CaC2O4. The precipitate is filtered, dissolved in dilute H2SO4 and the oxalate tit... JEE Advanced level
A mixture of oxalic acid (H2C2O4) and sodium oxalate is dissolved in water. A 25.0 mL portion needs 13.2 mL of 0.1000 M NaOH to the phenolphthalein end point (s... JEE Advanced level
0.0100 mol of FeC2O4 is dissolved in dilute H2SO4. Consider titration with 0.0200 M KMnO4 (oxidises both Fe^2+ and oxalate completely) and with 0.0200 M K2Cr2O7... JEE Advanced level
Equal amounts of the same reductant are titrated with KMnO4 under three conditions: acidic (to Mn^2+), neutral (to MnO2) and strongly basic (to MnO4^2-). Let th... JEE Advanced level