CBSE Class 12 Chemistry The d and f Block Elements MCQs Set 05

Question: Which of the following types of metals form the most efficient catalysts ?
(a) Alkali metals
(b) Alkaline earth metals
(c) Transition metals
(d) All of these
Answer: c

Question: The highest oxidation state exhibited by transition metals is
(a) + 7
(b) + 8 
(c) + 6
(d) + 5
Answer: b

Question: Which metal gives hydrogen gas on heating with hot concentrated alkali ?
(a) Ag
(b) Ni
(c) Zn
(d) Cu
Answer: c

Question: Magnetic moment of manganese in (NH₄)₂ MnBr₂ is
(a) 3.87 BM
(b) 5.91 BM 
(c) 4.89 BM
(d) 2.82 BM
Answer: b 

Question: Which one of the following reactions will occur on heatmg AgNO₃ above its melting point? 
(a) 2AgNO₃ → 2Ag + 2NO₂ + O₂
(b) 2AgNO₃ → 2Ag + N2 + 3O₂
(c) 2AgNO₃ → 2AgNO₂ + O₂
(d) 2AgNO₃ → 2Ag + 2NO + 2O₂
(e) 2AgNO₃ → Ag₂O + N₂O₃ + O₂
Answer: c

Question: The highest magnetic moment is shown by the transition metal ion with the configuration 
(a) 3d²
(b) 3d⁵
(c) 3d⁷
(d) 3d⁹ 
Answer: b

Question: Which of the following is philosopher’s wool? 
(a) ZnO
(b) HgO
(c) Ag₂O
(d) CuO
Answer: a

Question: Ferrous sulphate (FeSO₄ · 7H₂O) is known as 
(a) vermillion
(b) Glauber’s salt
(c) green vitriol
(d) Mohr’s salt
Answer: c

Question: In photography we use
(a) Agl
(b) NH₃
(c) AgCl
(d) AgBr
Answer: d

Question: Which of the following ions is colourless in solution ?
(a) V³⁺
(b) Cr³⁺ 
(c) Co²⁺
(d) Sc³⁺
Answer: d

Question: Due to lanthanide contraction
(a) Fe, Co, Ni have equal size
(b) Zr and Hf have equal size
(c) all ƒ-block ions have equal size
(d) all isoelectric ions have equal size
Answer: b

Question: Bronze is a mixture of 
(a) Pb + Sn
(b) Cu + Sn
(c) Cu + Zn
(d) Pb + Zn
Answer: b

Question: Effective magnetic moment of Sc³⁺ ion is 
(a) 1.73
(b) 0
(c) 5.92
(d) 2.83
(e) 3.87 
Answer: b

Question: The magnetic moment of Cu²⁺ ion is 
(a) 2.73
(b) zero
(c) 1.93
(d) 1.73 
Answer: d

Question: The ‘spin-only’ magnetic moment [in units of Bohr magneton, (μ_β )] of Ni²⁺ in aqueous solution would be (Atomic number of Ni = 28) 
(a) 2.84
(b) 4.90
(c) 0
(d) 1.73
Answer: a

Question: ‘Hydride gap’ is referred to which region of the periodic table ? 
(a) Groups 3, 4 and 5
(b) Groups 5, 6 and 7
(c) Groups 4, 5 and 6
(d) Groups 7, 8 and 9
(e) Groups 6, 7 and 8
Answer: d

Question: Which of the following transition metal ions will have definite value of magnetic moment ? 
(a) Sc³⁺
(b) Ti³⁺
(c) Cu³⁺
(d) Zn²⁺
Answer: b

Question: Which of the following ions has a magnetic moment of 5.93 BM ?
(Atomic number V = 23, Cr= 24, Mn= 25, Fe = 26)
(a) Mn²⁺
(b) Fe²⁺
(c) Cr²⁺
(d) y³⁺
(e) Cr³⁺
Answer: a

Question: Which of the following is used as purgative?
(a) HgS
(b) Hg₂Cl₂
(c) HgCl₂
(d) ZnSO₄ 
Answer: a

Question: Potassium permanganate acts as an oxidant in alkaline and acidic medium. The final products formed from KMnO₄ in the two conditions are respectively
(a) MnO^2- and Mn³⁺
(b) Mn³⁺ and Mn²⁺
(c) Mn²⁺ and Mn³⁺
(d) MnO₂ and Mn^2-
(e) Mn²⁺, MnO₂
Answer: d

Question: Mohr salt is made up of which combination of salt ?
(a) Ammonium sulphate and potash
(b) Ammonium sulphate and fe1Tous sulphate
(c) Ammonium sulphate and copper sulphate
(d) Ammonium sulphate and magnesium sulphate
Answer: b

Question: Which one of the following statements is not true with regard to transition elements ?
(a) They readily form complex compounds
(b) They show variable oxidation states
(c) All their ions are colourless
(d) Their ions contain partially filled d-electrons
Answer: c

Question: Mone! metal is an alloy of
(a) Cu, Ni, Fe, Mn
(b) Cu, Sn, Zn
(c) Cu, Sn, P
(d) Cu, Zn
Answer: a

Question: Which of the following group of transition metals is called coinage metals ?
(a) Cu, Ag, Au
(b) Ru, Rh, Pd
(c) Fe, Co, Ni
(d) Os, Ir, Pt
Answer: a

Question: Which of the following pair of transition metal ions, have the same calculated values of magnetic moment?
(a) Ti²⁺ and V²⁺
(b) Fe²⁺ and Cu²⁺
(c) Cr²⁺ and Fe²⁺
(d) Co²⁺ and Ti²⁺
Answer: c

Question: The gas obtained by reaction of K₄Fe(CN)₆ with cone. H₂SO₄ is 
(a) H₂S
(b) CO
(c) NO₂
(d) CO₂
Answer: b

Question: Formation of coloured ions by transition metals signifies
(a) absorption of light from UV range
(b) emission of light
(c) presence of unpaired electrons in sand p-orbitals
(d) complimentary colours to the absorbed light 
Answer: d

Question: Among the following the compound that is both paramagnetic and coloured is 
(a) K₂Cr₂O₇
(b) (NH₄ )2 [TiCl₆ ]
(c) VOSO₄
(d) K₃[Cu(CN)₄ ]
Answer: c

Question: Which of the following is not a characteristic of transition elements ?
(a) Variable oxidation states
(b) Formation of coloured compounds
(c) Formation of interstitial compounds
(d) Natural radioactivity
Answer: d

Question: The oxidation number of Mn in the product of alkaline oxidative fusion of MnO₂ is 
(a) 2
(b) 3 
(c) 4
(d) 6
Answer: d

Question: Among the following, the coloured compound is
(a) CuCl
(b) K₃[Cu(CN)₄]
(c) CuF₂
(d) [Cu(CH₃CN)₄]BF₄
Answer: c

Question: Hair dyes contain
(a) coppernitrate
(b) gold chloride
(c) silver nitrate
(d) copper sulphate
Answer: c