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प्रश्न
Transition metals can act as catalysts because these can change their oxidation state. How does \[\ce{Fe(III)}\] catalyse the reaction between iodide and persulphate ions?
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उत्तर
Reaction between iodide and persulphate ions is:
\[\ce{2I^{-} + S2O^{2-}8 ->[Fe(III)] I2 + 2SO^{2-}4}\]
Role of \[\ce{Fe(III)}\] ions:
\[\ce{2Fe^{3+} + 2I^{-} -> 2Fe^{2+} + I2}\]
\[\ce{2Fe^{2+} + S2O^{2-}8 -> 2Fe^{3+} + 2SO^{2-}4}\]
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संबंधित प्रश्न
Explain why is Fe3+ more stable than Fe2+?
Which metal in the first transition series (3d series) exhibits + 1 oxidation state most frequently and why?
Which of the following cations are coloured in aqueous solutions and why ?
Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element shows only +3 oxidation state?
Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iodide.
For M2+/M and M3+/M2+ systems, the E° values for some metals are as follows:
| Cr2+/Cr | −0.9 V |
| Mn2+/Mn | −1.2 V |
| Fe2+/Fe | −0.4 V |
| Cr3/Cr2+ | −0.4 V |
| Mn3+/Mn2+ | +1.5 V |
| Fe3+/Fe2+ | +0.8 V |
Use this data to comment upon:
- The stability of Fe3+ in acid solution as compared to that of Cr3+ or Mn3+ and
- the ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
How would you account for the following:
The d1 configuration is very unstable in ions.
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 ______.
Which of the following ions show higher spin only magnetic moment value?
(i) \[\ce{Ti^3+}\]
(ii) \[\ce{Mn2+}\]
(iii) \[\ce{Fe2+}\]
(iv) \[\ce{Co3+}\]
EΘ of Cu is + 0.34V while that of Zn is – 0.76V. Explain.
Answer the following question:
Which element of the first transition series has lowest enthalpy of atomisation?
Passing H2S gas into a mixture of Mn2+ and Ni2+, Cu2+, ions in an acidified aqueous solution precipitates.
Account for the following:
Transition metals form alloys.
The oxidation state of Fe in [Fe(CO)5] is ______.
Assertion (A): Transition metals have high enthalpy of atomisation.
Reason (R): Greater number of unpaired electrons in transition metals results in weak metallic bonding.
Which of the following transition metals shows +1 and +2 oxidation states?
Write the number of unpaired electrons in Cr3+.
(Atomic number of Cr = 24)
Account for the following:
Copper has an exceptionally positive `"E"_("M"^(2+)//"M")^0` value.
