Advertisements
Advertisements
Question
Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with iron (II) ions? Write the ionic equation for the reaction.
Advertisements
Solution
Potassium permanganate is prepared by fusion of MnO2 with an alkali metal hydroxide and an oxidising agent like KNO3. This produces the dark green K2MnO4, which disproportionates in a neutral or acidic solution to give permanganate.
\[\ce{2MnO2 + 4KOH + O2 -> 2K2MnO4 + 2H2O}\]
Potassium manganate is extracted with water and thereafter disproportionates in neutral or acidic solution to yield potassium permanganate.
\[\ce{3MnO^{2-}_4 + 4H^+ -> 2MnO^-_4 + MnO2 + 2H2O}\]
In an acidic medium of dilute sulphuric acid, KMnO4 acts as a strong oxidising agent, and it reacts as:
\[\ce{MnO^-_4 + 8H^+ + 5e- -> Mn^2+ + 4H2O}\]
Ferrous (Fe2+) ion solution to ferric (Fe3+) ion solution
\[\ce{MnO^-_4 + 8H+ + 5e- -> Mn^{2+} + 4H2O}\]
\[\ce{5Fe^{2+} -> 5Fe^{3+} + 5e-}\]
________________________________________________
\[\ce{MnO^-_4 + 5Fe^{2+} + 8H+ -> Mn^{2+} + 5Fe^{3+} + 4H2O}\]
RELATED QUESTIONS
Complete the following chemical equation
8MnO4- + 3S2O32- + H2O →
Complete the following chemical equation
Cr2O72- + 3Sn2+ + 14H+ →
Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?
Give an example and suggest a reason for the following feature of the transition metal chemistry:
The highest oxidation state is exhibited in oxoanions of a metal.
Complete the following equations:
`2MnO_4^(-)+16H^++5S^(2-)rarr`
Using IUPAC norms, write the formula of potassium trioxalatochromate(III).
Which of the following is amphoteric oxide?
\[\ce{Mn2O7, CrO3, Cr2O3, CrO, V2O5, V2O4}\]
In the form of dichromate, \[\ce{Cr (VI)}\] is a strong oxidising agent in acidic medium but \[\ce{Mo (VI)}\] in \[\ce{MoO3}\] \[\ce{and W (VI)}\] in \[\ce{WO3}\] are not because:
(i) \[\ce{Cr(VI)}\] is more stable than \[\ce{Mo(VI)}\] and \[\ce{and W(VI)}\].
(ii) \[\ce{Mo(VI)}\] and \[\ce{and W(VI)}\] are more stable than \[\ce{Cr(VI)}\].
(iii) Higher oxidation states of heavier members of group-6 of transition series are more stable.
(iv) Lower oxidation states of heavier members of group-6 of transition series are more stable.
When \[\ce{Cu^2+}\] ion is treated with \[\ce{KI}\], a white precipitate is formed. Explain the reaction with the help of chemical equation.
Potassium permanganate acts as an oxidant in neutral, alkaline as well as acidic media. The final products obtained from it in the three conditions are, respectively.
KMnO4 is coloured due to ______.
The oxidation state of manganese in the product obtained in a reaction of potassium permanganate and hydrogen peroxide in a basic medium is ______.
Complete the following ionic equation:
\[\ce{Cr2O^{2-}7 + 2OH^- ->}\]
Complete the reaction mentioning all the products formed:
\[\ce{2KMnO4 ->[\Delta]}\]
Which of the following ions will have a magnetic moment value of 1.73 BM.
\[\ce{Sc^3+, Ti^3+, Ti^2+, Cu^2+, Zn^2+}\]
Indicate the steps in the preparation of \[\ce{K2Cr2O2}\] from chromite ore.
Indicate the step in the preparation of K2Cr2O7 from chromite ore.
Indicate the steps in the preparation of K2Cr2O7 from chromite ore.
