d- and f-Block Elements
Topics
Chapter tests
See all →Top questions
See all →- Given below are two statements :Statement I : Ferromagnetism is considered as an extreme form of paramagnetism.Statement II : The number of unpaired electrons in a Cr^2+ ion (Z = 24) is the same as that of a Nd^3+ ion (Z = 60).In the light of the abo… Answer: 3. Statement I is true but Statement II is false Statement I is true: ferromagnetism is the extreme form of paramagnetism (domains a... 1
- Match List - I with List - IIList-I: A. Haber process B. Wacker oxidation C. Wilkinson catalyst D. Ziegler catalystList-II: I. Fe catalyst II. PdCl_2 III. [(PPh_3)_3RhCl] IV. TiCl_4 with Al(CH_3)_3Choose the correct answer from the options given belo… Answer: 3. A-I, B-II, C-III, D-IV Haber process: Fe catalyst (I). Wacker oxidation (ethene to ethanal): PdCl₂ (II). Wilkinson catalyst: [(PP... 1
- The pair of lanthanoid ions which are diamagnetic is Answer: 2. Ce⁴⁺ and Yb²⁺ Key idea: diamagnetic means no unpaired electrons, so 4f⁰ or 4f¹⁴ . mathrmCe⁴⁺ : 4f⁰ ; mathrmYb²⁺ : 4f¹⁴ . Both dia... 1
- 'Spin only' magnetic moment is same for which of the following ions?A. Ti^3+ B. Cr^2+ C. Mn^2+ D. Fe^2+ E. Sc^3+Choose the most appropriate answer from the options given below: Answer: 2. B and D only Key idea: μ=√(n(n+2)) BM, so equal unpaired electrons give equal moment. mathrmTi³⁺ ( d¹ ): 1 mathrmCr²⁺ ( d⁴ ): 4 m... 1
- The E^° value for the Mn^3+/Mn^2+ couple is more positive than that of Cr^3+/Cr^2+ or Fe^3+/Fe^2+ due to change of Answer: 4. d⁴ to d⁵ configuration Key idea: a high E^° for M³⁺/M²⁺ means M³⁺ is easily reduced to a very stable M²⁺ . mathrmMn³⁺ is d⁴ ; on... 1
- The reaction that does NOT take place in a blast furnace between 900 K to 1500 K temperature range during extraction of iron is : Answer: 2. Fe ₂ O ₃ + CO → 2FeO + CO ₂ Key idea: The blast furnace has temperature zones: the reduction of Fe₂O₃ to FeO by CO takes place in... 1