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प्रश्न
How would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
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उत्तर
In the presence of complexing reagents, the crystal field stabilization energy is greater than the third ionization enthalpy of cobalt. Thus, Co (II) is easily oxidized to Co (III).
संबंधित प्रश्न
Why +2 oxidation state of manganese is more stable?
Why do the transition elements have higher enthalpies of atomisation?
How would you account for the following : Transition metals form coloured compounds
Which of the d-block elements may not be regarded as the transition elements?
Calculate the number of unpaired electrons in the following gaseous ions:
Mn3+, Cr3+, V3+ and Ti3+. Which one of these is the most stable in an aqueous solution?
What are alloys?
Write the factors which are related to the colour of transition metal ions.
Why do transition elements show variable oxidation states ? In 3d series (Sc to Zn), which elements shows the maximum number of oxidation state and why ?
Explain why transition elements form alloys.
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
| Element | \[\ce{Fe}\] | \[\ce{Co}\] | \[\ce{Ni}\] | \[\ce{Cu}\] |
| Metallic radii/pm | 126 | 125 | 125 | 128 |
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) \[\ce{Cr^{3+}}\]
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) \[\ce{Ni}\]
Answer the following question:
Which element of the first transition series has lowest enthalpy of atomisation?
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?
On the basis of the figure given below, answer the following questions:
- Why Manganese has lower melting point than Chromium?
- Why do transition metals of 3d series have lower melting points as compared to 4d series?
- In the third transition series, identify and name the metal with the highest melting point.
The element with atomic number 53 belongs to
On strong heating AgNO3, the gases evolved are:-
Which one of the following characters tie of the transition metal is associated with higher catalytic activity?
Which property of transition metals enables them to behave as catalysts?
The compounds of \[\ce{Ti^4+}\] ions are colourless due to ______.
