Advertisements
Advertisements
प्रश्न
Write the chemical equation for the preparation of 4 KMnO from 2. MnO Why does purple colour of acidified permanganate solution decolourise when it oxidises Fe2- to Fe3+ ?
Advertisements
उत्तर
Chemical equations for the preparation of KMnO4 from MnO2
2MnO2 + 4KOH + O2 → 2K2MnO4 + 2H2O
`3MnO_4^2+4H -> 2MnO_4^- + 2 MnO_4^- + MnO_2 + 2H_2O `
\[\ce{ MnO_2 ->[Fused with oxidised][with air or KNO3]}MnO_4^{2-}\] maganate ion
\[\ce{ \underset{Manganate}{MnO_4^{2-}} ->[Electrolytic oxidation][in alkaline solution] MnO_4^- }\] permanganateion
Purple colour of acidified permanganate solution decolourise when it oxidises Fe2- + Fe3+
In acidic medium, Reduction
KMnO4 is behaving as oxidising Agent.
So, purple colour of acidified 4 KMnO solutions decolourises.
APPEARS IN
संबंधित प्रश्न
Complete the following equation :
`2MnO_4^(-)+6H^++5NO_2^(-)rarr`
Complete the following equations : 2 MnO2 + 4 KOH + O2 →
Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?
Name a member of the lanthanoid series that is well-known to exhibit +2 oxidation state.
Which of the following reactions are disproportionation reactions?
(a) \[\ce{Cu^{+} -> Cu^{2+} + Cu}\]
(b) \[\ce{3MnO^{-}4 + 4H^{+} -> 2MnO^{-}4 + MnO2 + 2H2O}\]
(c) \[\ce{2KMnO4 -> K2MnO4 + MnO2 + O2}\]
(d) \[\ce{2MnO^{-}4 + 3Mn^{2+} + 2H2O -> 5MnO2 + 4H^{+}}\]
Which of the following is amphoteric oxide?
\[\ce{Mn2O7, CrO3, Cr2O3, CrO, V2O5, V2O4}\]
The product formed upon heating methyl bromide with potassium tert-butoxide is
Potassium dichromate when heated with concentrated sulphuric acid and a soluble chloride, gives brown-red vapours of ______.
Complete the following ionic equation:
\[\ce{Cr2O^{2-}7 + 2OH^- ->}\]
Indicate the steps in the preparation of \[\ce{K2Cr2O7}\] from chromite ore.
