Redox Titration (permanganometry)

Question

In an acidic medium permanganometric titration, 20 mL of 0.05 M oxalic acid solution was titrated against potassium permanganate of concentration 0.02 M. What volume of permanganate is required to reach the end point?

RankGuru · Accepted Answer

Permanganate titrations are redox reactions in which the equivalents of oxidant equal the equivalents of reductant at the end point. In acidic medium the permanganate ion gains five electrons, MnO_4^- + 8H^+ + 5e^- → Mn^{2+} + 4H_2O, so its n-factor is 5. Oxalic acid is oxidised at both carbon atoms, C_2O_4^{2-} → 2CO_2 + 2e^-, giving it an n-factor of 2. The milliequivalents of oxalic acid = molarity × volume × n-factor = 0.05 × 20 × 2 = 2.0 meq. Setting this equal to the permanganate milliequivalents, 0.02 × V × 5 = 2.0, gives 0.1 × V = 2.0, so V = 20 mL. Option 10 mL would result from using an n-factor of 5 for oxalic acid as well, ignoring its true value of 2. Option 50 mL arises from treating permanganate with an n-factor of 2. Option 8 mL comes from omitting the oxalic acid n-factor entirely. This equivalence approach reflects the NCERT redox-titration method. Plausibility check: because permanganate transfers more electrons per mole than oxalate, the equal equivalents balance out here to give a coincidentally equal volume, which is dimensionally consistent.

Redox Titration (permanganometry)

Select the correct option:

🔒 Solution Hidden from View

More principles related to practical chemistry Practice Questions

On a paper chromatogram, a coloured component travelled 2.7 cm from the baseline while the solvent f...

A standard solution was prepared by dissolving 0.63 g of pure oxalic acid dihydrate in water and mak...

Mohr's salt, prepared in the laboratory from ferrous sulphate and ammonium sulphate, behaves differe...

Steam distillation is chosen to purify aniline from a mixture containing non-volatile impurities. Wh...

Two liquids in a mixture have boiling points of 78 degrees and 110 degrees Celsius and are completel...

Elemental analysis of an organic compound gives carbon 40.0 percent, hydrogen 6.7 percent, and oxyge...

An organic compound containing both nitrogen and sulphur, when subjected to sodium fusion and the ex...

During the qualitative detection of nitrogen by Lassaigne's test, the appearance of a Prussian blue ...

A student boils the sodium fusion extract of an organic compound and adds sodium nitroprusside, obta...

The sodium fusion extract of an organic compound is acidified with dilute nitric acid and treated wi...

In Kjeldahl's estimation, 1.4 g of an organic compound liberated ammonia that was exactly neutralise...

By Duma's method, 0.5 g of an organic compound on combustion produced 112 mL of nitrogen gas measure...

About This Question

Solution