MCQ Chapter 8 The d – and f – Block Elements Class 12 Chemistry

Please refer to The d – and f – Block Elements MCQ Questions Class 12 Chemistry below. These MCQ questions for Class 12 Chemistry with answers have been designed as per the latest NCERT, CBSE books and syllabus issued for the current academic year. These objective questions for The d – and f – Block Elements will help you to prepare for the exams and get more marks.

The d – and f – Block Elements MCQ Questions Class 12 Chemistry

Please see solved MCQ Questions for The d – and f – Block Elements in Class 12 Chemistry. All questions and answers have been prepared by expert faculty of standard 12 based on latest examination guidelines.

Question. Zn does not show variable valency because of
(a) complete d-subshell
(b) inert pair effect
(c) 4s²-subshell
(d) None of these     

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

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

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

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     

Question. A compound in which a metal ion M^x+ (Z = 25)has a spin only magnetic moment of ✓24 BM. The number of unpaired electrons in the compound and the oxidation state of the metal ion are respectively 
(a) 4 and 2
(b) 5 and 3
(c) 3 and 2
(d) 4 and 3
(e) 3 and 1     

Question. Stainless steel has iron and
(a) Cr
(b) Cu
(c) Co
(d) Zn   

Question. An ƒ-shell containing 6 unpaired electrons can exchange
(a) 6 electrons
(b) 9 electrons 
(c) 12 electrons
(d) 15 electrons     

Question. Mercury is a liquid metal because
(a) it has a completely filled s-orbital
(b) it has a small atomic size
(c) it has a completely filled d-orbital that prevents d-d overlapping of orbitals
(d) it has a completely filled d-orbital that causes d-d overlapping       

Question. The following two reactions HNO₃ with Zn are given as (equations are not balanced)
I. Zn+ cone. HNO₃ → Zn (NO₃)₂ + X + H₂O (A)
II. Zn + di!. HNO₃ → Zn (NO₃)₂+ Y + H₂O (B)
In reactions I and II, the compounds X and Y respectively, are
(a) NO₂ and NO
(c) NO and NO₂
(b) NO₂and NO₂
(d) NO₂ and NH₄NO₃     

Question. The lanthanoid which exhibits + 4 oxidation 
(a) Pm
(b) Sm
(c) Ce
(d) Gd   

Question. The magnetic moment of a transition metal ion is √15 BM. Therefore, the number ofunpaired electrons present in it, is
(a) 3
(b) 4
(c) 1
(d) 2   

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     

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 ]   

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     

Question. What is the oxidation state of iron in Mohr’s salt? 
(a) + 3
(b) 0
(c) + 2
(d) + 1   

Question. Which of the following compounds volatilises on heating?
(a) MgCI₂
(b) HgCI₂
(c) CaCI₂
(d) FeCI₃     

Question. MnO^–₄ reacts with bromide ion in alkaline medium to give 
(a) MnBr₄
(b) MnOBr₂
(c) MnO₂, BrO^–₃
(d) MnO, BrO   

Question. Atomic radius of Ti, Zr and Hf vary 
(a) Ti > Zr > Hf
(b) Ti < Zr < Hf
(c) Ti < Hf < Zr
(d) Ti < Zr = HF     

Question. The correct statement is 
(a) the earlier members of lanthanoid series resemble calcium in their chemical properties
(b) the extent of actinoid contraction is almost the same as lanthanoid contraction
(c) in general, lanthanoid and actinoids do not show variable oxidation states
(d) Ce⁴⁺ in aqueous solution is not known       

Question. In context with the transition elements, which of the following statement is incorrect ? 
(a) In addition to the normal oxidation state, the zero oxidation state is also shown by these elements in complexes
(b) In the highest oxidation state, the transition metal shows basic character and form cationic complexes
(c) In the highest oxidation state of the first five transition elements (Sc to Mn), all the 4s and 4d electrons are used for boncling
(d) Once the d⁵ configuration is exceeded, the tendency to involve all the 3d electrons in bonding decreases   

Question. Transition metal ions show colour because 
(a) they absorb light
(b) they emit light
(c) they are paramagnetic
(d) they exhibit d -d transition   

Question. The magnetic moment of a salt containing Zn²⁺ ion is
(a) 0
(b) 1.87 
(c) 5.92
(d) 2       

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

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     

Question. When hydrogen peroxide is added to acidified potassium dichromate, a blue colour is produced due to formation of
(a) CrO₃
(b) Cr₂O₃
(c) CrO₅ 
(d) CrO₄^2-
(e) Cr₂O₇^2-     

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     

Question. Corrosive sublimate (HgCI₂ ) can be used to distinguish between 
(a) formic acid and acetic acid
(b) acetaldehyde and butanone
(c) formaldehyde and propanone
(d) All of the above     

Question. KMnO₄ (acidic/alkaline) is not decolourised by 
(a) Mohr salt
(b) oxalic acid
(c) benzene
(d) propene       

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

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         

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

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

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

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

Question. Which of the oxide of manganese is amphoteric?
(a) MnO₂
(b) Mn₂O₃ 
(c) Mn₂O₇
(d) MnO     

Question. A transition metal ion exists in its highest oxidation state. It is expected to behave as
(a) a chelating agent
(b) a central metal in a coordination compound
(c) an oxidising agent
(d) a reducing agent       

Question. Which of the following compound is expected to be coloured ? 
(a) Ag₂SO₄
(b) CuF₂
(c) MgF₂
(d) CuCl     

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     

Question. Pick out the correct statements from the following.
I. Cobalt (III) is more stable in octahedral complexes.
II. Zinc forms coloured ions or complexes.
III. Most of the d-block elements and their compounds are ferromagnetic.
IV. Osmium shows (VIII) oxidation state.
V. Cobalt (II) is more stable in octahedral complexes.
(a) I and II
(b) I and III
(c) II and IV
(d) I and IV
(e) II and V       

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⁺     

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

Question. Which of the following is not a member of 3d-transition series ? 
(a) Fe
(c) Au
(b) Co
(d) Cu     

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

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   

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   

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

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   

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

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

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⁺     

Question. Excess of KI reacts with CuSO₄ solution and then Na₂S₂O₃ solution is added to it. Which of the statements is incorrect for this reaction ? 
(a) Cu₂I₂ fonned
(b) Cul₂ is formed
(c) Na Na₂S₂O₃ is oxidised
(d) Evolved I₂ is reduced     

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

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

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

Question. Cl₂ + HgO → ?
(a) Cl₂O + HgCl
(c) ClO + HgCl
(b) Cl₂O + HgCl₂
(d) ClO + HgCl₂   

Question. When oxyhaemoglobin changes to deoxyhaemoglobin, Fe²⁺ ion changes from 
(a) diamagnetic to paramagnetic
(b) paramagnetic to diamagnetic
(c) diamagnetic to ferromagnetic
(d) paramagnetic to ferromagnetic     

Question. The magnetic moment of a transition metal ion is 3 .87 BM. The number of unpaired electrons present in it is 
(a) 2
(b) 3
(c) 4
(d) 5   

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   

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     

Question. Gun metal is
(a) Cu + Zn
(b) Cu + Sn + Zn
(c) Cu + Sn
(d) Zn + Sn     

Question. The atomic numbers of vanadium (V), chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionisation enthalpy ? 
(a) V
(b) Cr
(c) Mn
(d) Fe   

Question. Formation of coloured solution is possible when metal ion in the compound contains
(a) paired electrons
(b) lone pair of electrons
(c) unpaired electrons
(d) None of these       

Question. Which of the following pairs of elements cannot form an alloy ? 
(a) Zn, Cu
(b) Fe, Hg
(c) Fe, C
(d) Hg, Na     

Question. Match the following Columns.

Codes
     A  B  C  D 
(a) 1  3  5  4
(b) 2  3  5  1
(c) 4  3  5  1
(d) 4  5  3  1
(e) 5  1  2  3