Give reasons for the following.
Transition elements act as catalysts.
It is difficult to obtain oxidation
State greater than two for copper
CrO is basic but Cr2O3 is amphoteric.
Answers
Answer:
Transition metals and their compounds function as catalysts either because of their ability to change oxidation state or, in the case of the metals, to adsorb other substances on to their surface and activate them in the process. All this is explored in the main catalysis section.
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After removal of two electrons they will have fully filled d-orbitals which acquires extra stability,so it is difficult to obtain oxidation state greater than 2 for Cu,Niand Zn.
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In other words, it has less electrons available in its valence shell and is electron deficient. There is also a high effective nuclear charge. As a result, it can accept electrons and behave as an acid. Since in Cr2O3 chromium is in higher oxidation state than in CrO, therefore it is amphoteric while Cro is basic.
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