Select the correct statements for the d-block and f-block elements:
A. The maximum oxidation state shown by manganese is +6.
B. \(Sc^{3+}\) (Scandium) is colourless
C. Brass is an alloy of Copper and Zinc
D. Lanthanide series included a total of 16 elements
E. \(V_2O_5\) (Vanadium Pentaoxide) is used in the manufacturing of sulphuric acid (by contact process).
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is option 3: B, C and E only.
Let us analyze each statement:
A. The maximum oxidation state shown by manganese is +6: This is incorrect. Manganese's highest oxidation state is +7, achieved in compounds like KMnO₄ (potassium permanganate).
B. Sc³⁺ (Scandium) is colourless: This is correct. Sc³⁺ has no unpaired electrons in its d orbitals, resulting in no d-d electron transitions and a colourless ion.
C. Brass is an alloy of Copper and Zinc: This is correct. Brass is a widely used alloy with a composition of roughly 70% copper and 30% zinc.
D. Lanthanide series included a total of 16 elements: This is incorrect. The lanthanide series begins at Lanthanum ($La$, $Z=57$) and ends at Lutetium ($Lu$, $Z=71$), which spans exactly 15 elements in total. All fifteen share highly similar chemical characteristics and are grouped together in standard textbook classifications.
E. V₂O₅ (Vanadium Pentaoxide) is used in the manufacturing of sulphuric acid (by contact process): This is correct. V₂O₅ acts as a catalyst in the contact process for sulphuric acid production by converting SO₂ to SO₃.
Therefore, only statements B, C, and E are true, making option (3) the correct answer.