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प्रश्न
Predict which of the following will be coloured in the aqueous solution?
Ti3+, V3+, Cu+, Sc3+, Mn2+, Fe3+ and Co2+. Give reasons for each.
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उत्तर १
Only the ions that have electrons in the d-orbital and for which the d-d transition is possible will be coloured. The ions in which d-orbitals are empty or completely filled will be colourless as no d-d transition is possible in those configurations.
| Element | Atomic Number | Ionic State | Electronic configuration in ionic state |
| Ti | 22 | Ti3+ | [Ar] 3d1 |
| V | 23 | V3+ | [Ar] 3d2 |
| Cu | 29 | Cu+ | [Ar] 3d10 |
| Sc | 21 | Sc3+ | [Ar] |
| Mn | 25 | Mn2+ | [Ar] 3d5 |
| Fe | 26 | Fe3+ | [Ar] 3d5 |
| Co | 27 | Co2+ | [Ar] 3d7 |
From the above table, it can be easily observed that only Sc3+ has an empty d-orbital and Cu+ has completely filled d-orbitals. All other ions, except Sc3+ and Cu+, will be coloured in aqueous solution because of d-d transitions.
उत्तर २
Those ions that have one or more unpaired electrons are coloured. Ti3+, V3+, Mn2+, Fe3+ and Co2+ are coloured. Cu+ and Sc3+ are colourless.
संबंधित प्रश्न
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
Write the factors which are related to the colour of transition metal ions.
NF3 is possible, but NF5 is not. Why?
The transition metals show _________ character because of the presence of unpaired· electrons and Cu+ is ____________ because of its electronic configuration is [Ar]3d10
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Electronic configuration of Mn2+ is ____________.
Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d5. What is its atomic number?
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because ______.
Why is \[\ce{HCl}\] not used to make the medium acidic in oxidation reactions of \[\ce{KMnO4}\] in acidic medium?
Transition elements show magnetic moment due to spin and orbital motion of electrons. Which of the following metallic ions have almost same spin only magnetic moment?
(i) \[\ce{Co^{2+}}\]
(ii) \[\ce{Cr^{2+}}\]
(iii) \[\ce{Mn^{2+}}\]
(iv) \[\ce{Cr^{3+}}\]
Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.
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Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other in:-
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?
The disproportionation of \[\ce{MnO^{2-}_4}\] in acidic medium resulted in the formation of two manganese compounds A and B. If the oxidation state of Mn in B is smaller than that of A, then the spin-only magnetic moment (µ) value of B in BM is ______. (Nearest integer)
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Explain the magnetic properties of d-block (or transition) elements.
A coordination compound has the formula \[\ce{CoCl3.4NH3}\]. It precipitates silver ions as AgCl and its molar conductance corresponds to a total of two ions.
Based on this information, answer the following question:
- Deduce the structural formula of the complex compound.
- Write the IUPAC name of the complex compound.
- Draw the geometrical isomers of the complex compound.
