Advertisements
Advertisements
Question
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because ______.
Options
\[\ce{CO2}\] is formed as the product.
Reaction is exothermic.
\[\ce{MnO^{-}4}\] catalyses the reaction.
\[\ce{MnO^{2+}}\] acts as autocatalyst.
Advertisements
Solution
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because \[\ce{MnO^{2+}}\] acts as autocatalyst.
Explanation:
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because \[\ce{Mn^{2+}}\] acts as an autocatalyst.
Reduction half \[\ce{Mno^{-}4 + 8H^+ + 5e^- -> Mn^{2+} + 4H2O] × 2}\]
Oxidation half \[\ce{C2O^{2-}4 -> 2CO2 + 2e] × 5}\]
Overall equation \[\ce{2Mno^{-}4 + 16H^+ + 5C2O^{2-}4 -> 2Min^{2+} + 10CO2 + 8H2O}\]
End point of this reaction Colourless to light pink.
APPEARS IN
RELATED QUESTIONS
How would you account for the following?
Transition metals exhibit variable oxidation states.
Calculate magnetic moment of `Fe_((aq))^(2+) ion (Z=26).`
What are the transition elements? Write two characteristics of the transition elements.
|
`E_((M^(2+)/M)` |
Cr | Mn | Fe | Co | Ni | Cu |
| -0.91 | -1.18 | -0.44 | -0.28 | -0.25 | -0.34 |
From the given data of E0 values, answer the following questions :
(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive
(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements
(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.
Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?
Why does the density of transition elements increase from Titanium to Copper? (at. no. Ti = 22, Cu = 29)
The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
\[\ce{KMnO4}\] acts as an oxidising agent in acidic medium. The number of moles of \[\ce{KMnO4}\] that will be needed to react with one mole of sulphide ions in acidic solution is ______.
Although fluorine is more electronegative than oxygen, but the ability of oxygen to stabilise higher oxidation states exceeds that of fluorine. Why?
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
Which one of the following characters tie of the transition metal is associated with higher catalytic activity?
Agcl is soluble in NH4OH. The solubility is due to the information of:-
Match List - I with List - II.
| List - I | List - II | ||
| (A) | [Fe(CN)6]3− | (i) | 5.92 BM |
| (B) | [Fe(H2O)6]3+ | (ii) | 0 BM |
| (C) | [Fe(CN)6]4− | (iii) | 4.90 BM |
| (D) | [Fe(H2O)6]2+ | (iv) | 1.73 BM |
Choose the correct answer from the options given below.
Give reasons for the following statement:
Transition metals and most of their compounds show paramagnetic behaviour.
How is the variability in oxidation states of transition metals different from that of p-block elements?
The oxidation state of Fe in [Fe(CO)5] is ______.
Complete the following reaction and justify that it is a disproportionation reaction:
\[\ce{3MnO^{2-}4 + 4H^+ -> \underline{}\underline{}\underline{}\underline{} + \underline{}\underline{}\underline{}\underline{} + 2H2O}\]
A pair of coloured ions is ______.
Explain the magnetic properties of d-block (or transition) elements.
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with H2S.
