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प्रश्न
Which of the following characteristics of transition metals is associated with their catalytic activity?
पर्याय
Paramagnetic nature
Colour of hydrated ions
High enthalpy of atomisation
Variable oxidation states
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उत्तर
Variable oxidation states
Explanation:
Transition metals have a tendency to have varying oxidation states, which allows them to create unstable intermediates and provide a novel reaction path with a lower Ea. As a result, transition metals have catalytic activity.
संबंधित प्रश्न
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element shows only +3 oxidation state?
Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
Compare the stability of +2 oxidation state for the elements of the first transition series.
Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
How would you account for the following?
Zr (Z = 40) and Hf (Z = 72) have almost identical radii.
Dissociation of H2S is suppressed 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) \[\ce{Cr^{3+}}\]
Ionisation enthalpies of Ce, Pr and Nd are higher than Th, Pa and U. Why?
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
The E° value for the Mn2+/Mn2+ couple is more positive than that of Cr3+/Cr2+ or Fe3+/Fe2+ due to the change of:
