Short Answer TypeAccount for the following :
E° value for the Mn3+/Mn2+ couple is highly positive (+1.57 V) as compared to Cr3+/Cr2+.
Mn2+ exists in 3d5 configuration which is a half-filled configuration which provides extra stability to the Metal Ion. While Mn3+ will exist in 3d4 configuration which is less stable than 3d5. Hence the conversion from 3+ to 2+ is very feasible. Hence E° value is more. while in
Cr+3 exist in 3d3 half-filled d orbital (3 e; electrons in t2g ) extra stability is attained by Cr+3 than Cr+2. Hence Cr+3 →Cr+2 is less feasible. And hence it has less reduction potential as compare to Mn+3/Mn+2.
Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.
How is the variability in oxidation states of transition metals different from that of the p-block elements?
An element has atomic mass 93 g mol–1 and density 11.5 g cm–3. If the edge
the length of its unit cell is 300 pm, identify the type of unit cell.
Calculate the number of unit cells in 8.1 g of aluminium if it crystallizes in a
f.c.c. structure. (Atomic mass of Al = 27 g mol–1)
Give reasons :
In stoichiometric defects, NaCl exhibits Schottky defect and not Frenkel
defect.
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