CBSE Class 12 Chemistry Transition Elements Worksheet

Question. What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid?
(a) Cr₂O₇^2- and H₂O are formed
(b) CrO₄^2- is reduced to +3 state of Cr
(c) CrO₄^2- is oxidized to +7 state of Cr
(d) Cr³⁺ and Cr₂O₇^2- are formed
Answer : A

Question. Which of the following oxides of manganese is amphoteric?
(a) MnO₂
(b) Mn₂O₃
(c) Mn₂O7
(d) MnO
Answer : A

Question. In which of the following compounds manganese has oxidation number equal to that of iodine in KIO₄ ?
(a) Potassium manganate
(b) Potassium permanganate
(c) Manganous chloride
(d) Manganese chloride
Answer : B

Question. The correct order of ionic radii of Y³⁺, La³⁺, Eu³⁺ and Lu³⁺ is
(a) La³⁺ < Eu³⁺ < Lu³⁺ < Y³⁺
(b) Y³⁺ < La³⁺ < Eu³⁺ <Lu³⁺
(c) Y³⁺ < Lu³⁺ < Eu³⁺ < La³⁺
(d) Lu³⁺ < Eu³⁺ < La³⁺ < Y³⁺
(Atomic nos. Y =39, La = 57, Eu = 63, Lu = 71)
Answer : C

Question. For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order?
(a) Mn > Fe > Cr > Co
(b) Fe > Mn > Co > Cr
(c) Co > Mn > Fe > Cr
(d) Cr > Mn > Co > Fe
Answer : A

Question. Which of the following compound is called Turnbull’s blue?
(a) Ferricyanide
(b) Ferrous ferricyanide
(c) Ferrous cyanide
(d) Ferri-ferrocyanide
Answer : B

Question. A compound of a metal ion Mx+ (Z = 24) has a spin only magnetic moment of 15 Bohr Magnetons. The number of unpaired electrons in the compound are
(a) 2
(b) 4
(c) 5
(d) 3
Answer : D

Question. The roasting of HgS in air produces
(a) HgO
(b) HgSO₃
(c) HgSO₄
(d) Hg
Answer : D

Question. When MnO₂ is fused with KOH, a coloured compound is formed, the product and its colour is:
(a) K₂MnO₄, purple green
(b) KMnO₄, purple
(c) Mn₂O₃, brown
(d) Mn₃O₄, black
Answer : A

Question. If an aqueous solution of KCN is added to a solution of ferrous salt then the complex formed is represented by
(a) [Fe(CN)₆]^4-
(b) [Fe(CN)₆]^3-
(c) [Fe(H₂O)₆]³⁺
(d) [Fe(H₂O)₆]²⁺
Answer : A

Question. Mercury (I) chloride sublimes, when this compound is heated and the vapours it gives off are cooled the substance collected consists of
(a) Mercury (II) chloride
(b) Mercury (I) and Mercury (II), chlorides
(c) Mercury (II) chloride and mercury
(d) Mercury
Answer : D

Question. In neutral or faintly alkaline medium, thiosulphate is quantitatively oxidized by KMnO₄ to
(a) SO₃^2–
(b) SO₄^2–
(c) SO₂
(d) SO₅^2–
Answer : B

Question. An excess of Na₂S₂O₃ reacts with aqueous CuSO₄ to give
(a) CuS₂O₃
(b) Cu₂S₂O₃
(c) Na₂[Cu(S₂O₃)₂]
(d) Na₄[Cu₆(S₂O₃)₅]
Answer : D

Question. Which of the following oxides of Cr is amphoteric
(a) CrO₂
(b) Cr₂O₃
(c) CrO₅
(d) CrO₃
Answer : A

Question. Consider the following statements
(I) La(OH)₃ is the least basic among hydroxides of lanthanoids.
(II) Zr⁴⁺ and Hf⁴⁺ posses almost the same ionic radii.
(III) Ce⁴⁺ can as an oxidizing agent.
Which of the above is/are true ?
(a) (I) and (III)
(b) (II) and (III)
(c) (II) only
(d) (I) and (II)
Answer : B

Numeric Value Answer

Question. The number of water molecule(s) directly bonded to the metal centre in CuSO₄.5H₂O is
Answer : 4

Question. Out of the following, how many oxides are acidic.
MnO, Mn₂O₃, MnO₂, MnO₃, Mn₂O₇
Answer : 3

Question. What is the oxidation states of Cr in butterfly structure.
Answer : 6

Question. The oxidation number of Mn in the product of alkaline oxidative fusion of MnO₂ is
Answer : 6

Question. A light blue coloured compound (A) on heating gives a block compound (B) which reacts with glucose to give a red compound (C). After the completion of reaction, how many metal oxides are formed?
Answer : 2

Q1. Give reasons for the following:-

(a) As compared to elements of the first transition series, heavier transition metals of second & third transition series show more frequent metal - metal bonding.

(b) Elements of second and third d series have similar radii.

(c) The unipositive transition metal ion have d" configuration.

(d) Scandium (II) is virtually unknown.

(e) Titanium (IV) is more stable than Titanium (II) or Titanium (III).

(f) Oxidation states in transition elements vary from each other by unity (eg V(ll) V(IlI) V(JV) V(V) whereas oxidation states of non transition states normally differ by a unit of two.

(g) In non transition elements; lower transition state is favoured by heavier elements whereas in transition elements higher transition state is favoured by heavier elements.  

TRANSITION ELEMENTS

Q1. Give reasons for the following:-

(a) As compared to elements of the first transition series, heavier transition metals of second & third transition series show more frequent metal – metal bonding.

(b) Elements of second and third d series have similar radii.

(c) The unipositive transition metal ion have dn configuration.

(d) Scandium (II) is virtually unknown.

(e)Titanium (IV) is more stable than Titanium (II) or Titanium (III).

(f) Oxidation states in transition elements vary from each other by unity (eg V(II) V(III) V(IV) V(V) whereas oxidation states of non transition states normally differ by a unit of two.

(g) In non transition elements; lower transition state is favoured by heavier elements whereas in transition elements higher transition state is favoured by heavier elements.

(h) E⁰M⁺² /M value for Mn, Ni & Zn is more negative expected.

(i) Highest Mn fluoride is MnF4 with Mn in +4 O.S. whereas highest Mn oxide is Mn₂O₇ with Mn in +7 O.S.

(j) For Cu Δ _iH0₁ = 745 KJ/mol whereas Δ _iH0₂ = 1940 KJ/mol, Inspite of very high second ionization enthalpy more stable O.S. of Cu in aqueous medium is +2

(k) V₂O₃ is basic while V₂O₅ is amphoteric

(l) Lanthanides resemble each other more closely than do members of ordinary transition series

(m) La & Lu do not show any colour

(n) Actinides show greater range of O.S. as compared to lanthanides.

(o) Ionization enthalpy of early actinides is lower than that of early lanthanides.

(p) Study of actinides is comparatively difficult.