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प्रश्न
Explain why is Fe3+ more stable than Fe2+?
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उत्तर
Electronic configuration of Fe2+ : 1s2 2s2 2p6 3s2 3p6 3d6
Electronic configuration of Fe3+ : 1s2 2s2 2p6 3s2 3p6 3d5
Due to the presence of half filled ‘d’ orbital, Fe3+ is more stable than Fe2+.
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संबंधित प्रश्न
Give reasons:
Transition metals show variable oxidation states.
How would you account for the following : Transition metals form coloured compounds
In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomization of zinc is the lowest, i.e., 126 kJ mol−1. Why?
To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
What is meant by ‘disproportionation’?
What are inner transition elements?
How would you account for the following?
Zr (Z = 40) and Hf (Z = 72) have almost identical radii.
An analysis shows that FeO has a non-stoichiometric composition with formula Fe0.95O. Give reason.
The transition metals show _________ character because of the presence of unpaired· electrons and Cu+ is ____________ because of its electronic configuration is [Ar]3d10
How is potassium dichromate prepared from chrome iron ore?
Why do transition metals exhibit higher enthalpy of atomization?
Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds?
Transition elements form binary compounds with halogens. Which of the following elements will form \[\ce{MF3}\] type compounds?
(i) \[\ce{Cr}\]
(ii) \[\ce{Co}\]
(iii) \[\ce{Cu}\]
(iv) \[\ce{Ni}\]
A solution of \[\ce{KMnO4}\] on reduction yields either a colourless solution or a brown precipitate or a green solution depending on pH of the solution. What different stages of the reduction do these represent and how are they carried out?
The halides of transition elements become more covalent with increasing oxidation state of the metal. Why?
Match the catalysts given in Column I with the processes given in Column II.
| Column I (Catalyst) | Column II (Process) |
| (i) \[\ce{Ni}\] in the presence of hydrogen | (a) Zieglar Natta catalyst |
| (ii) \[\ce{Cu2C12}\] | (b) Contact process |
| (iii) \[\ce{V2O5}\] | (c) Vegetable oil to ghee |
| (iv) Finely divided iron | (d) Sandmeyer reaction |
| (v) \[\ce{TiCl4 + Al (CH3)3}\] | (e) Haber's Process |
| (f) Decomposition of KCIO3 |
Identify the metal and justify your answer.
\[\ce{MO3F}\]
Account for the following:
In case of transition elements, ions of the same charge in a given series show progressive decrease in radius with increasing atomic number.
It has been observed that first ionization energy of 5 d series of transition elements are higher than that of 3d and 4d series, explain why?
A metallic ion 'M' reacts with chloride ion to form white precipitate which is readily soluble in aqueous ammonia. Identify 'M'?
On adding NaOH, solution to the aqueous solution of K2CrO7 the colour of the solution changes from
Which of the following ions will exhibit colour in aqueous solution?
The number of terminal oxygen atoms present in the product B obtained from the following reactions is:
\[\ce{FeCr2O4 + Na2CO3 + O2 -> A + Fe2O3 + CO2}\]
\[\ce{A + H^+ -> B + H2O + Na^+}\]
Consider the following standard electrode potentials (E° in volts) in aqueous solution:
| Element | M3+/M | M+/M |
| Al | - 1.66 | +0.55 |
| Tl | + 1.26 | -0.34 |
Based on these data, which of the following statements is correct?
Write the number of unpaired electrons in Cr3+.
(Atomic number of Cr = 24)
Write the ionic equation for reaction of KI with acidified KMnO4.
Why are interstitial compounds well known for transition metals?
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iron (II) solution.
For M2+/M and M3+/M2+systems, the EΘ 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 ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
