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प्रश्न
Answer the following question:
Which element of the first transition series has lowest enthalpy of atomisation?
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उत्तर
Zinc is the element of the first transition series that has the lowest enthalpy of atomisation. The electronic configuration of zinc is: \[\ce{3d^10 4s^2}\]. This is because it has filled 3d-subshell and filled 4s-subshell so no unpaid electron is available for metallic bonding.
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संबंधित प्रश्न
Which is a stronger reducing agent, Cr2+ or Fe2+ and why?
Which of the d-block elements may not be regarded as the transition elements?
Write down the number of 3d electrons in the following ion:
Cu2+
Indicate how would you expect the five 3d orbitals to be occupied for this hydrated ions (octahedral).
Which one of the following ions is coloured?
Explain why Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)
Transition metals with highest melting point is ____________.
Which of the following will not act as oxidising agents?
(i) \[\ce{CrO3}\]
(ii) \[\ce{MoO3}\]
(iii) \[\ce{WO3}\]
(iv) \[\ce{CrO^{2-}4}\]
Transition elements show high melting points. Why?
Identify A to E and also explain the reactions involved.
Why are fluorides of transition metals more stable in their higher oxidation state as compared to the lower oxidation state?
Catalytic hydrogenation of benzene gives
Which does not belong to first transition series?
Which of the following species has maximum magnetic momentum?
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)
Which of the following ions has the electronic configuration 3d6?
(Atomic number: Mn = 25, Co = 27, Ni = 28)
The second ionization enthalpies of chromium and manganese are 1592 and 1509 kJ/mol respectively. Explain the lower value of Mn.
What is the oxidation state of chromium in chromate ion and dichromate ion?
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.
Match List-I with List-II.
| List-I | List-II |
| A. Haber process | I. Fe catalyst |
| B. Wacker oxidation | II. PdCl2 |
| C. Wilkinson catalyst | III. [(PPh3)3RhCl] |
| D. Ziegler catalyst | IV. TiCl4 with Al(CH3)3 |
Choose the correct answer from the options given below:
The E° value for the Mn2+/Mn2+ couple is more positive than that of Cr3+/Cr2+ or Fe3+/Fe2+ due to the change of:
