Permanganatometry

Permanganatometry is a titrimetric (volumetric) method for the determination of substances based on oxidation reactions involving permanganate ions.

Permanganometric titration is based on a redox process involving a pair of Mn (VII) / Mn (II) (E ^o = + 1.52 V) in an acidic medium:

{\mathsf {MnO_{4}^{-}+8H^{+}+5e^{-}\rightleftharpoons Mn^{2+}+4H_{2}O}}

{\ displaystyle {\ mathsf {MnO_ {4} ^ {-} + 8H ^ {+} + 5e ^ {-} \ rightleftharpoons Mn ^ {2 +} + 4H_ {2} O}}}

{\ mathsf {MnO_ {4} ^ {-} + 8H ^ {+} + 5e ^ {-} \ rightleftharpoons Mn ^ {{2 +}} + 4H_ {2} O}}

When using a solution of potassium permanganate as a titrant, it is possible to determine, for example, iron ions, hydrogen peroxide , oxalates :

{\mathsf {5H_{2}O_{2}+2KMnO_{4}+3H_{2}SO_{4}\rightarrow 5O_{2}+2MnSO_{4}+K_{2}SO_{4}+8H_{2}O}}

{\ displaystyle {\ mathsf {5H_ {2} O_ {2} + 2KMnO_ {4} + 3H_ {2} SO_ {4} \ rightarrow 5O_ {2} + 2MnSO_ {4} + K_ {2} SO_ {4} + 8H_ {2} O}}}

{\ mathsf {5H_ {2} O_ {2} + 2KMnO_ {4} + 3H_ {2} SO_ {4} \ rightarrow 5O_ {2} + 2MnSO_ {4} + K_ {2} SO_ {4} + 8H_ {2 } O}}

The titration endpoint is determined without an indicator by the appearance of the intrinsic violet color of the MnO ₄ ^- ions.

Sources

edited by Ishchenko A.A. t.1 // Analytical chemistry and physico-chemical methods of analysis. - M .: Academia, 2010 .-- 352 p. - ISBN 978-5-7695-5816-0 .

Permanganatometry

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