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प्रश्न
What is meant by ‘disproportionation’?
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उत्तर
The oxidation and reduction of a substance at the same time as a result of a chemical reaction is called disproportionation.
संबंधित प्रश्न
Account for the following:
Cr2+ is a strong reducing agent.
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element has the highest m.p?
Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
The \[\ce{E^{\circ}_{(M^{2+}/M)}}\] value for copper is positive (+0.34 V). What is possible reason for this? (Hint: consider its high ΔaH° and low ΔhydH°)
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 would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
in basic medium.
Give reasons Iron has the higher enthalpy of atomization than that of copper.
Dissociation of H2S is suppressed in acidic medium.
Why do transition metals exhibit higher enthalpy of atomization?
Two metallic elements A and B have the following standard oxidation potentials: A = 0·40v B = - 0·80v. What would you expect if element A was added to an aqueous salt solution of element B? Give a reason for your answer.
Give reasons for the following:
The transition metals generally form coloured compounds.
Reactivity of transition elements decreases almost regularly from Sc to Cu. Explain.
Match the solutions given in Column I and the colours given in Column II.
| Column I (Aqueous solution of salt) |
Column II (Colour) |
| (i) \[\ce{FeSO2.7H2O}\] | (a) Green |
| (ii) \[\ce{NiCl2.4H2O}\] | (b) Light pink |
| (iii) \[\ce{MnCl2.4H2O}\] | (c) Blue |
| (iv) \[\ce{CoC12,6H2O}\] | (d) Pale green |
| (v) \[\ce{Cu2 Cl2}\] | (e) Pink |
| (f) Colourless |
Answer the following question:
Which element of the first transition series has highest second ionisation enthalpy?
Which of the following maxm magnetic moment?
Which of the following ions will exhibit colour in aqueous solution?
Give reasons for the following statement:
Zn, Cd, and Hg are soft metals.
Which of the following characteristics of transition metals is associated with their catalytic activity?
Which property of transition metals enables them to behave as catalysts?
