JEE Main Previous Year Papers Questions With Solutions Chemistry Elements of d-Block,f-Block and Complexes

JEE Main Previous Year Papers Questions With Solutions Chemistry  Elements of d-Block, f-Block and Complexes

Ans.(2) A square planer complex is formed by hybridisation of s, p_x, p_y and d_x2 -d_y2 atomic orbitals.

2.The type of isomerism present in nitro- pentamine chromium (III) chloride is (2002)
(1)optical          2)   linkage
3) ionization    4)   polymerisation
Ans.(2) The nitro group can attach to metal through nitrogen as (-N0₂) or through oxygen as nitrito (-ONO).

3.CH₃-Mg-Br is an organo metallic compound due to  (2002)
(1)Mg-Br bond      2)   C-Mg bond
3) C-Br bond         4)   C-H bond
Ans.(2)Bond between C atom of organic molecule and metal atom.

4.Most common oxidation states of Ce (cerium) are     (2002)
(1)+2, + 3         2)   +2, + 4
3) +3, + 4       4)   +3, +5
Ans.(4)Common oxidation states of Ce(Cerium) are +3 and + 4.

5.Arrange Ce⁺³, La⁺³, Pm⁺³ and Yb⁺³ in increasing order of their ionic radii (2002)
(1)Yb⁺³ < Pm⁺³ < Ce⁺³ < La⁺³
(2)Ce⁺³ < Yb⁺³ < Pm⁺³ < La⁺³
(3)Yb⁺³ < Pm⁺³ < La⁺³ < Ce⁺³
(4)Pm⁺³ < La⁺³ < Ce⁺³ < Yb⁺³
Ans.(1) According to their positions in the periods, these values are in the order :

Ans.(2) A more basic ligand forms stable bond with metal ion, Cl^– is most basic amongst all.

7.Ammonia forms the complex ion [Cu(NH₃)₄]²⁺with copper ions in alkaline solutions but not in acidic solutions. What is the reason for it ? (2003)
(1)In acidic solutions protons coordinate with ammonia molecules forming NH₄ ions and NH₃ molecules are not available
(2)In alkaline solutions insoluble Cu(OH)₂ is precipitated which is soluble in excess of any alkali.
(3)Copper hydroxide is an amphoteric substance
(4)In acidic solutions hydration protects copper ions
Ans.(1) Cu²⁺ forms complex with free NH_y (4)

8.One mole of the complex compound Co(NH₃)₅C1₃, gives 3 moles of ions on dissolution in water. One mole of the same complex reacts with two moles of AgN0₃ solution to yield two moles of AgCl_(s). The structure of the complex is          (2003)
(1)[Co(NH₃)₃Cl₃].2NH₃
(2)[Co(NH₃)₄C1₂]C1.NH₃
(3)[Co(NH₃)₄C1]C1₂.NH₃ 4) [Co(NH₃)₅C1]C1₂
Ans.

9.In the coordination compound, K₄[Ni(CN)₄], the oxidation state of nickel is             (2003)
1)0  2) + 1          3) + 2           4) – l
Ans.

10.A reduction in atomic size with increase in atomic number is a characteristic of elements of          (2003)
(1)d-block 2) f-block
3) radioactive series 4) high atomic masses
Ans.(2) f-block elements show a regular decrease in atomic size due to lanthanide/actinide contraction.

11.The coordination number of central metal atom in a complex is determined by (2004)
(1)The number of ligands around a metal ion bonded by sigma bonds
(2)The number of only anionic ligands bonded to the metal ion
(3)The number of ligands around a metal ion bonded by sigma and pi- bonds both
(4)The number of ligands around a metal ion bonded by pi-bonds
Ans.

12.Which one of the following complexes in an outer orbital complex ?      (2004)
(1)[Fe(CN)₆]⁴–              2) [Ni(NH₃)₆]²⁺
3) [Co(NH₃)₆]³⁺             4) [Mn(CN)₆]^4_
Ans.

13.Coordination compound have great importance in biological systems. In this context which of the following statements is incorrect ?     (2004)
‘ 1) Chlorophylls are green pigments in plants and contains calcium
(2)Carboxypeptidase – A is an enzyme and contains zinc
(3)Cyanocobalamin is B₁₂ and contains cobalt
(4)Haemoglobin is the red pigment of blood and  contains iron
Ans.(3)Chlorophyll contains magnesium instead of calcium.

14.Cerium(Z=58)is an important member of the lanthanoids. Which of the following statements about cerium is incorrect ? (2004)
(1)The common oxidation states of cerium are +3 and +4
(2)Cerium (IV) acts as an oxidizing agent
(3)The +4 oxidation state of cerium is not knownin solutions                                        .
(4)The +3 oxidation state of cerium is more stable than the +4 oxidation state
Ans.(3) Oxidation potential of Ce(IV) in aqueous solution is supposed to be -ve i.e. -0.784 V at 25°C.

15.Which one the following has largest number of isomers? (R-= alkyl group, en = ethylenediamine) (2004)
1) [Ru(NH₃)₄C1₂+]      2)         [Co(en)₂Cl₂]⁺
3) [Ir(PR₃)₂ H(CO)]²⁺      4)   [Co(NH₃)₅C1]²⁺
Ans.(2)Geomerical and optical isomerisum.

16.The correct order of magnetic moments (spin only values in B.M.) among is               (2004)
(1)[MnClJ^2- > [CoCl₄]-² > [Fe(CN)₆r
(2)[Fe(CN)₆]’⁴ > [CoClJ²– > [MnClJ^2-
(3)[Fe(CN)J^4- > [MnClJ²– > [CoClJ^2-
(4)[MnClJ^2- > [Fe(CN)J⁴– > [CoClJ^2-
Ans.(1) Number of unpaired e” in Mn²⁺ is 5, Co²⁺ is 3 and Fe²⁺ is zero.

17.The oxidation state of  Cr in  the complex[Cr(NH₃)₄Cl₂]⁺ is  (2005)
(1)+3     2) +2           3) +1           4)0
Ans.

18.Calomel (Hg₂Cl₂) on reaction with ammonium hydroxide gives                                    (2005)
(1)HgNH₂Cl       2)   NH₂-Hg-Hg-Cl
3) Hg₂0                  4)    HgO
Ans.(1) Reaction between calomel and ammonia is Hg₂Cl₂ + 2NH₄OH ->Hg + Hg(NH₂ )C1 + 2H₂

19.The IUPAC name of the coordination compound K₃[Fe(CN)₆] is     (2005)
(1)Potassium hexacyanoferrate (II)
(2)Potassium hexacyanoferrate (III)
(3)Potassium hexacyanoiron (II)
(4)tripotassium hexcyanoiron (II)
Ans.(2) Complex of Fe³⁺ is ferrate(III).

20.Which of the following compounds shows optical isomerism?     (2005)
1) [Cu(NH₃)₄]⁺²               2)    [ZnClJ-²
3) [Cr(C₂0₄)₃]-³                4)    [Co(CN)₆]-³
Ans.(3) The optical isomers are.

Ans.

22.The value of the ‘spin only’ magnetic moment for one of the following configurations is 2.84 BM. The correct one is       (2005)
(1)d⁴ (in strong ligand filed)
(2)d⁴ (in weak ligand field)
(3)d³ (in weak as well as in strong fields)
(4)d⁵ (in strong ligand field)
Ans.

23.The IUPAC name for the complex [Co(N0₂)(NH₃)₅]C1₂ is (2006)
(1)nitrito-N-pentaamminecobalt (III) chloride
(2)nitrito-N-pentaamminecobalt (II) chloride
(3)pentaammine nitrito-N-cobalt (II) chloride
(4)pentaammine nitrito-N-cobalt (III) chloride
Ans.

24.Nickel (Z = 28) combines with a uninegative monodentate ligand X~ to form a paramagnetic complex [NiXJ^2-. The number of unpaired electron(s) in the nickel and geometry of this complex ion are, respectively       (2006)
(1)one, tetrahedral      2) two, tetrahedral
3) one, square planar   4) two, square planar
Ans.

25.In Fe(CO)₅, the Fe-C bond possesses (2006)
(1)k -character only
(2)both 0 and n characters
(3)ionic character 4) a -character only…
Ans.(2) Because of back bonding both o and kbonds are present.

26.How many EDTA (ethylenediaminetetraacetic acid) molecules are required to make an octahedral complex with a Ca²⁺ ion ? (2006)
(1)Six 2) Three 3) One 4) Two
Ans.(3) EDTA^4- is hexadentate ligand.

27.Lanthanoid contraction is caused due to (2006)
(1)The appreciable shielding on outer electrons by 4f electrons from the nuclear charge
(2)The appreciable shielding on outer electrons by 5d electrons from the nuclear charge
(3)The same effective nuclear charge from Ce to Lu
(4)The imperfect shielding on outer electrons by 4f electrons from the nuclear charge
Ans.(4) Poor slidding by f-electrons.

28.Identify the incorrect statement among the, following                                                (2007)
(1)d-Block elements show irregular and erratic chemical properties among themselves
(2)La and Lu have partially filled d orbitals and no other partially filled orbitals
(3)The chemistry of various lanthanoids is very similar
(4)4f and 5f orbitals are equally shielded
Ans.(4) 4f and 5f belongs to different energy levels, hence the shielding effect is on them is not the same. Shielding of 4f is more than 5f.

Ans.

30.The actinoids exhibits more number of oxida­tion states in general than the lanthanoids. This is because          (2007)
(1)The 5f orbitals are more buried than the 4f orbitals
(2)There is a similarity between 4f and 5f orbit­als in their angular part of the wave function
(3)The actinoids are more reactive than the lanthanoids
(4)The 5f orbitals extend further from the nucleus than the 4f orbitals

Ans.(4) The actinoids exhibit more number of oxi­dation states in general than the lanthanoids. This is because the 5f orbitals extend further from the nucleus than the 4f orbitals.

31.The coordination number and the oxidation state of the element ‘E’ in the complex [E(en)₂(C₂0₄)]N0₂(where ‘en’ is ethylene diamine) are, respectively,   (2008)
1) 6 and 2 2) 4 and 2 3) 4 and 3 4) 6 and 3

Ans.

32.Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the main reason being (2008)
(1)4f orbitals more diffused than the 5f orbitals
(2)Lesser energy difference between 5f and 6d than between 4f and 5d orbitals
(3)More energy difference between 5f and 6d than between 4f and 5d orbitals
(4)More reactive nature of the actinoids than the lanthanoids

Ans.(2) Being lesser energy difference between 5f and 6d than 4f and 5d orbitals.

33.In which of the following octahedral complexes of Co (at. no. 27), will be magnitude of A₀ be the highest ?  (2008)
1) [Co(CN)₆]³“              2) [Co(C₂0₄)₃]³–
3) [Co(H₂0)₆]³⁺             4) [Co(NH₃)₆]³⁺

Ans.

34.Knowing that the chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements in incorrect?(2009)
(1)Because of the large size of the Ln(III) ions the bonding in its compounds is predominantly ionic in character
(2)The ionic sizes of Ln(III) decreases in general with increasing atomic number
(3)Ln(III) compounds are generally colourless
(4)Ln(III) hydroxides are mainly basic in character

Ans.(3) Ln⁺³ compounds are mostly coloured.

35.Which of the following has an optical isomer?(2009)
1) [C0(NH₃)₃C1]\           2) [CO(en) (NH₃)₂]²⁺
3) [C0(H₂0)₄(en)]³⁺        4) [CO(en)₂(NH₃)₂]³⁺

Ans.(4) It is an octahedral complex of the type [M(AA)₂X₂] where AA is bidentate ligand.

36.In context with the transition elements, which of the following statements is incorrect ?(2009)
(1)In addition to the normal oxidation states, the zero oxidation state is also shown by these elements in complexes
(2)In the highest oxidation states, the transition metal show basic character and form cationic complexes.
(3)In the highest oxidation states of the first five transition elements (Sc to Mn), all the 4s and 3d electrons are used for bonding.
(4)Once the d³ configuration is exceeded, the tendency to involve all the 3d electrons in bonding decreases.
Ans.(2) In higher oxidation states transition elements show acidic nature.

37.Which of the following pairs represents linkage isomers ?   (2009)
(1)[Cu (NHj )₄ ][PtCl₄ ] and [Pt(NH,)₄][CuCl₄]
(2)[Pd (PPh₃ )₂ (NCS)₂ ] and[Pd(PPh₃)₂(SCN)₂]
(3)[CO(NH₃)₅N0₃]S0₄and [co(NH₃)₅S0₄]N0₃
(4)[PtCl₂(NH₃)₄]Br₂ and [PtBr₂ (NH₃)₄]C1₂
Ans.

38.A solution containing 2.675 g of CoCl₃. 6NH₃ (molar mass = 267.5g mol’¹) is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of AgN0₃ to give 4.78g of AgCl (molar mass = 143.5 g mol^-1). The formula of the complex is (At. Mass of Ag = 108u)                   (2010)
1)   [Co(NH₃)₆]C1₃         2)   [CoC1₂(NH₃)JC1
‘ 3)    [CoC1₃(NH₃)₃]        4)    [CoC1(NH₃)₅]C1₂
Ans.

39.Which one of the following has an optical isomer? (en = ethylenediamine)           (2010)
(1)[Zn(en) (NH₃)₂]²⁺   2)   [Co(en)₃]³⁺
3)[Co(H₂0)₄(en)]³⁺           4)         [Zn(en)₂]²⁺
Ans.

40.The magnetic moment (spin only) of [NiClJ^2]-is     (2011)
1) 2.82 BM           2) 1.41 BM
(3)82 BM             4) 5.46 BM
Ans.

41.Which of the following facts about the complex [Cr(NH₃)₆]Cl₃ is wrong ?    (2011)
(1)The complex is an outer orbital complex
(2)The complex gives white precipitate with silver nitrate solution.
(3)The complex involves d²sp³ hybridisation and is octahedral in shape
(4)The complex is paramagnetic
Ans.

42.In context of the lanthanoids, which of the following statements is not correct ? (2011)
(1)Because of similar properties the separation of lanthanoids is not easy
(2)Availability of 4f electrons results in the formation of compounds in + 4 state for all the members of the series
(3)There is a gradual decrease in the radii of the members with increasing atomic number in the series
(4)All the members exhibit + 3 oxidation state
Ans.(2) All the Lanthanides can not form + 4  oxidation state.

43.Which among the following will be named as dibromidohis (ethylenediamine) chromium (m) bromide ?    (2012)
1) [Cr(en)₃]Br₃₃             2) [Cr(en)₂Br₂]Br
3) [Cr(en)BrJ-                4) [Cr(en)Br₂]Br
Ans.

44.Which of the following complex species is not expected to exhibit optical isomerism ? (2013)
1) [Co(en)₃]³⁺                 2) [Co(en)₂C/₂]⁺
3) [Co(NH₃)C/₃]       4) [Co(en)(NH₃)₂C/₂]⁺
Ans.(3) [Co(NH₃)₃C/₃] do not exhibit optical isomers but othee exhibit.

45.Which of the following arrangements does not represent the correct order of the property stated against it ?  (2013)
(1)V²⁺< CF⁺ < Mn²⁺ < Fe²⁺ :Paramagnetic behaviour
(2)Ni²⁺ < Co²⁺ < Fe²⁺ < Mn²⁺ : Ionic size
(3)Co³⁺ < Fe³⁺ < Cr³⁺ < Sc³⁺ :Stability in aqueous solution
(4)Sc < Ti < Cr < Mn :Number of oxidation states
Ans.

Ans.(3) Order of wavelength of colours Red > Yellow > Green > Blue

Ans.

Ans.(2)Two bidentate and two monodentative – ligands are present.

Ans.(3) Change transfer from oxygen to manganese

Ans. (1) Ferrocyanide is blue.