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प्रश्न
Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with iron (II) ions? Write the ionic equation for the reaction.
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उत्तर
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
\[\ce{MnO^-_4 + 8H+ + 5e- -> Mn^{2+} + 4H2O}\]
\[\ce{5Fe^{2+} -> 5Fe^{3+} + 5e-}\]
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\[\ce{MnO^-_4 + 5Fe^{2+} + 8H+ -> Mn^{2+} + 5Fe^{3+} + 4H2O}\]
संबंधित प्रश्न
Complete the following equation:
\[\ce{2MnO4- + 6H+ + 5NO2- ->}\]
Complete the following chemical equations :
Cu + H2SO4(conc.) →
Name a member of the lanthanoid series that is well-known to exhibit +2 oxidation state.
Answer the following question.
When MnO2 is fused with KOH in the presence of KNO3 as an oxidizing agent, it gives a dark green compound (A). Compound (A) disproportionates in an acidic solution to give a purple compound (B). An alkaline solution of compound (B) oxidizes KI to compound (C) whereas an acidified solution of compound (B) oxidizes KI to (D). Identify (A), (B), (C), and (D).
\[\ce{KMnO4}\] acts as an oxidising agent in alkaline medium. When alkaline \[\ce{KMnO4}\] is treated with \[\ce{KI}\], iodide ion is oxidised to ______.
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.
The product formed upon heating methyl bromide with potassium tert-butoxide is
KMnO4 is coloured due to ______.
What is the effect of pH on dichromate ion solution?
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 reaction mentioning all the products formed:
\[\ce{2KMnO4 ->[\Delta]}\]
Complete the reaction mentioning all the products formed:
\[\ce{Cr2O^{2-}7 + 3H2S + 8H^+ ->}\]
Indicate the steps in the preparation of K2Cr2O7 from chromite ore.
Indicate the steps in the preparation of \[\ce{K2Cr2O7}\] from chromite ore.
Indicate the steps in the preparation of \[\ce{K2Cr2O7}\] from chromite ore.
Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with oxalic acid? Write the ionic equation for the reaction.
Indicate the steps in the preparation of \[\ce{K2Cr2O7}\] from chromite ore.
