CBSE Questions for Class 12 Engineering Chemistry The D-And F-Block Elements Quiz 11 - MCQExams.com

$$CuSO_{4}$$ is paramagnetic while $$ZnSO_{4}$$ is diamagnetic because
  • $$Cu^{2+}$$ ion has $$3d^{9}$$ configuration while $$Zn^{2+}$$ ion has $$3d^{10}$$ configuration
  • $$Cu^{2+}$$ ion has $$3d^{5}$$ configuration while $$Zn^{2+}$$ ion has $$3d^{6}$$ configuration
  • $$Cu^{2+}$$ has half filled orbitals while $$Zn^{2+}$$ has fully filled orbitals
  • $$CuSO_{4}$$ is blue in colour while $$ZnSO_{4}$$ is white.
Chrome yellow is chemically known as 
  • lead chromate
  • lead sulphate
  • lead iodide
  • basic lead acetate
Which of the following complex ion has a magnetic moment same as $$[Cr(H_2O)_6]^{3+}$$?
  • $$[Mn(H_2O)_6]^{4+}$$
  • $$[Mn(H_2O)_6]^{3+}$$
  • $$[Fe(H_2O)_6]^{3+}$$
  • $$[Cu(H_3H)_4]^{2+}$$
A blood red colour is obtained when ferric chloride solution reacts eith:
  • $$KCN$$
  • $$KSCN$$
  • q$$K_4[Fe(CN)_6]$$
  • $$K_3[Fe(CN)_6]$$
These questions consists of two statements each, printed as assertion and reason, while answering these questions you are required to choose any one of the following responses.

Assertion : $$CrO_3$$ reacts with $$HCl$$ to form thornyl chloride gas.
Reason : Chromyl chloride $$(CrO_2Cl_2)$$ has tetrahedral shape.
  • If both assertion and reason are true and the reason is a correct explanation of assertion
  • If both assertion and reason are true but reason is not a correct explanation of assertion
  • If assertion is true but the reason is false
  • If assertion is false but the reason is true
Transition metal and their compounds are used as catalysts in industry and in biological system. For example, in the contact process, vanadium compounds in the $$+5$$ state $$(V_2O_5$$ or $$VO_3^$$) are used to oxidise $$SO_2$$ to $$SO_3$$: 
$$SO_2 + \frac{1}{2}O_2 \overset{V_2O_5}{\rightarrow}SO_3$$
It is thought that the actual oxidation process takes place in two stages. In the first step, $$V^{5+}$$ in the presence of oxide ions converts $$SO_2$$ to $$SO_3$$. At the same time, $$V^{5+}$$ is reduced to $$V^{4+}$$. $$2V^{5+}+O^{2-} + SO_2 2V^{4+}+ SO_3$$. In the second step, $$V^{5+}$$ is regenerated from $$V^{4+}$$ by oxygen : 
$$2V^{4+}+\frac{1}{2}O_2 \rightarrow 2V^{5+} + O^{2-}.$$ 
The overall process is, of course, the sum of these two steps: 
$$SO_2 + \frac{1}{2}O_2 \rightarrow SO_3$$


During the course of the reaction 
  • catalyst undergoes changes in oxidation state
  • catalyst increases the rate constant
  • catalyst is regenerated in its original form when the reactants form the products
  • all are correct
Amongst $$Tif_{6}^{2-}, CoF_{6}^{3-}, Cu_2Cl_2 and NiCl_{4}^{2-}$$ the colourless species are:
  • $$CoF_{6}^{3-}$$ and $$NiCl_{4}^{2-}$$
  • $$TiF_{6}^{2-}$$ and $$CoF_{6}^{3-}$$
  • $$Cu_2Cl_2$$ and $$NiCl_{4}^{2-}$$
  • $$TiF_{6}^{2-}$$ and $$Cu_2Cl_2$$
When $$CO_2$$ is passes into aqueous $$K_2CrO_4$$  solution, this changes to another colour. What is the another colour?
  • Black
  • Yellow
  • Pink
  • Orange

Which of the following pairs has almost same colour?
  • $$_{60}Nd^{3+}.\ _{69}Tm^{3+}$$
  • $$_{70}Yb^{3+},\ _{59}Pr^{3+}$$
  • $$_{63}Eu^{2+},\ _{65}Tb^{3+}$$
  • $$_{64}Gd^{3+},\ _{67}Ho^{3+}$$
What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid?
  • $$Cr_2O_{7}^{2-}$$ and $$H_{2}O$$ are formed.
  • $$CrO_{7}^{2-}$$ is reduced to $$+3$$ state of $$Cr$$.
  • $$CrO_{7}^{2-}$$ is oxidized to $$+7$$ state of $$Cr$$.
  • $$Cr^{3+}$$ and $$Cr_{2}O_{7}^{2-}$$ are formed.
What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid?
  • $$CrO_{4}^{2-}$$ is oxidized to +7 state of Cr
  • $$Cr^{3+}$$ and $$Cr_{2}O_{7}^{2-}$$ are formed
  • $$Cr_{2}O_{7}^{2-}$$ and $$H_{2}O$$ are formed
  • $$CrO_{4}^{2-}$$ is reduced to +3 state of Cr
The actinoids exhibit more oxidation states in general than the lanthanoids. This is because:
  • the 5f orbitals are more buried than the 4f orbitals.
  • there is a similarity between 4f and 5f orbitals in their angular part of the wave function.
  • the actinoids are more reactive than the lanthanoids.
  • the 5f orbitals extend further from the nucleus than the 4f orbitals.
A larger number of oxidation states are exhibited by the actinides than those by the lanthanides. The main reason being:
  • more reactive nature of the actinides than the lanthanides
  • $$4f$$ orbitals are more diffused than the $$5f$$ orbitals
  • lesser energy difference between $$5f$$ and $$6d$$ orbitals than between $$4f$$ and $$5d$$ orbitals
  • more energy difference between $$5f$$ and $$6d$$ orbitals than between $$4f$$ and $$5d$$ orbitals

The actinoids exhibit more number of oxidation states in general than lanthanoids because: 
  • the 5f orbitals are more buried than the 4f orbitals
  • there is a similarity between 4f and 5f orbitals in their angular part of the wave function
  • the actinoids are more reactive than the lanthanoids
  • the 5f orbitals extend further from the nucleus than the 4f orbitals
Statements that are true of d-and f-block elements are:

1. The colour of $$K_{2}Cr_{2}O_{7}$$ is due to d-d transition.

 Actinides have larger number of oxidation states than lanthanides.

 Tripositive ions of $$Pr(At. No. =59)$$ and $$Tm(At. No. =69)$$ have the same (green) colour.

 Actinides have paramagnetic moments less than theoretically predicted values.
  • 2,3,4
  • 1,2,3
  • 2,4
  • 1,2,4
Regarding the magnetic properties of lanthanides and actinides the correct statement is:
  • Lanthanides are weakly paramagnetic while actinides are strongly paramagnetic.
  • Quenching of orbital contribution is greater in lanthanides than in actinides.
  • 5f electrons in actinides are too diffuse and are less effectively shielded which results in considerable quenching of orbital contribution, and hence the magnetic moments of actinides are significantly less than theoretically predicted values.
  • Because of diffused f-electrons there is no quenching of orbital contribution towards magnetic moment.
Transition metals are less reactive than alkali metals because they have:
  • high ionisation potential and low melting point
  • high ionisation potential and high melting point
  • low ionisation potential and low melting point
  • low ionisation potential and high melting point
The larger number of oxidation states are exhibited by the actinides than those by lanthanoids, the main reason being:
  • more energy difference between 5f and 6d than between 4f and 5d orbitals
  • more reactive nature of the actinoids than the lanthanoids
  • 4f orbitals more diffused than the 5f orbitals
  • lesser energy difference between 5f and 6d than between 4f and 5d orbitals
Dipositive and tripositive ions of A and B possess same number of electron pairs, but different number of unpaired electrons. Both are paramagnetic. Identify the atomic numbers of A and B.
  • 24, 25
  • 29, 30
  • 21, 22
  • 22, 24
Atoms of the transition element are smaller than those of the s-block elements. This is because of  :
  • usual contraction in size across a horizontal period
  • orbital electrons are added to the penultimate d-shell rather than to the outermost shell of the atom
  • both A and B
  • none of the above
The value of the magnetic moment of a particular ion is 2.83 Bohr magneton. The ion is :
  • $$Fe^{2+}$$
  • $$Ni^{2+}$$
  • $$Mn^{2+}$$
  • $$Co^{3+}$$
Increasing order of magnetic moment among the following species is:
$$\displaystyle Na^{+},Fe^{+3},Co^{+2},Cr^{+2}$$
  • $$Na^{+} < Co^{2+} < Cr^{2+} < Fe^{3+}$$
  • $$Na^{+} < Fe^{3+} < Cr^{2+} < Co^{2+}$$
  • $$Cr^{2+} < Co^{2+} < Na^{+} < Fe^{3+}$$
  • $$Co^{2+}< Na^{+} < Cr^{2+} < Fe^{3+}$$
Transition elements form complexes very readily because of:
  • small cation size
  • vacant d-orbitals
  • large nuclear charge
  • all of the above
Select the correct order of ions with respect to their ionic radii.
  • $$Y^{3+} < Lu^{3+} < Eu^{3+} < La^{3+}$$
  • $$Lu^{3+} < Y^{3+} < Eu^{3+} < La^{3+}$$
  • $$Lu^{3+} < Eu^{3+} < La^{3+} < Y^{3+}$$
  • $$La^{3+} < Eu^{3+} < Lu^{3+} < Y^{3+}$$
Magnetic moments of $$M^{2+}$$ ions (divalent cations ) of 3d-series in the decreasing order is : 
$$Zn^{2+} > Sc^{2+} = Cu^{2+} > Ti^{2+} = Ni^{2+} > V^{2+}=Co^{2+} > Cr^{2+} = Fe^{2+} > Mn^{2+}$$

Is the above statement true?
  • True
  • False
What would happen when as solution of potassium chromate is treated with an excess of dilute nitric acid?
  • $$Cr^{3+}$$ and $$Cr_2O^{2-}_7$$ are formed
  • $$Cr_2O^{2-}_7$$ang $$H_2O$$ are formed
  • $$CrO^{2-}_4$$ is reduced to $$Cr^{3+}$$
  • None of the above
Spin only magnetic moment of the compound $$Hg[Co{(SCN)}_{4}]$$ is :
  • $$\sqrt 3$$
  • $$\sqrt 15$$
  • $$\sqrt 24$$
  • $$\sqrt 8$$
Least paramagnetic property is shown by:
  • $$Fe$$
  • $$Mn$$
  • $$Ni$$
  • $$Cu$$
Which of the following statements are correct with reference to the ferrous and ferric ions?
  • $${Fe}^{3+}$$ gives brown color with potassium ferricyanide
  • $${Fe}^{2+}$$ gives blue precipitate with potassium ferricyanide
  • $${Fe}^{3+}$$ gives red color with potassium thiocyanate
  • $${Fe}^{2+}$$ gives brown color with ammonium thiocyanate
An inorganic salt is lemon yellow in colour. It becomes orange in colour like methyl orange when it is acidic and again becomes yellow when it is alkaline. The inorganic salt will be :
  • copper nitrate
  • ferric chloride
  • potassium chromate
  • potassium ferricyanide
Copper becomes green when exposed to moist air for a long period of time due to the
  • formation of a layer of cupric oxide on the surface of copper.
  • formation of a layer of basic carbonate of copper on the surface of copper.
  • formation of a layer of cupric hydroxide on the surface of copper.
  • none of the above.
$$FeCl_3.6H_2O + C(CH_3)_2 (CH_3O)_2 \rightarrow$$ Products.
Reaction products are:
  • $$FeCl_3,\ CH_3OH$$ and $$CH_3COCH_3$$
  • $$CH_3O)_3Fe,\ HCl$$ and $$H_2O$$
  • $$FeCl_2,\ HCl$$ and $$CH_3COCH_3$$
  • $$Fe(OH)_3,\ FeCl_3$$ and $$CH_3COCH_3$$
In an experiment when placed in the weak magnetic field, calomel was slightly repelled by the magnetic field. This experimental observation suggests that:
  • $$Hg^+$$ ion has no unpaired electron.
  • mercurous ion has a formula $$Hg_2^{2+}$$ instead of $$Hg^+$$
  • this experimental observation is not correct and actually mercurous salts are paramagnetic due to $$6s$$ unpaired electron
  • sometimes mercurous ion may exist as $$Hg_2^{2+}$$
Column-I (Alloys)Column-II (Constituents)
(A) TiCl$$_4$$ (p) Adams catalyst in reduction
(B) PdCl$$_2$$ (q) In preparation of (CH$$_3$$)$$_2$$SiCl$$_2$$
(C) Pt/PtO(r) Used as the Natta catalyst in polythene production
(D) Cu(s) Wake process for converting C$$_2$$H$$_4$$  to CH$$_3$$CHO
  • (A) $$\rightarrow$$ s ; (B) $$\rightarrow$$ r ; (C) $$\rightarrow$$ p ; (D) $$\rightarrow$$ q
  • (A) $$\rightarrow$$ q ; (B) $$\rightarrow$$ s ; (C) $$\rightarrow$$ p ; (D) $$\rightarrow$$ r
  • (A) $$\rightarrow$$ r ; (B) $$\rightarrow$$ s ; (C) $$\rightarrow$$ p ; (D) $$\rightarrow$$ q
  • (A) $$\rightarrow$$ p ; (B) $$\rightarrow$$ s ; (C) $$\rightarrow$$ r ; (D) $$\rightarrow$$ q
How many of the following ions have the same magnetic moments?
Fe$$^{2+}$$ Mn$$^{2+}$$ Cr$$^{2+}$$ Ni$$^{2+}$$
  • 1
  • 2
  • 3
  • 4
A metal $$M$$ which is not affected by strong acids like conc. $$HNO_3, conc. H_2SO_4$$ and conc. solution of alkalies like $$NaOH, KOH$$ forms $$MCl_3$$ which finds use for toning in photography. The metal $$M$$ is :
  • $$Ag$$
  • $$Hg$$
  • $$Au$$
  • $$Cu$$
Transition metals and their compounds catalyse reactions because:
  • they have completely filled $$s$$ - subshell.
  • they have a comparable size due to poor shielding of d-subshell.
  • they introduce an entirely new reaction mechanism with lower activation energy.
  • they have variable oxidation states.
Catalytic activity of transition metals depends on:
  • their ability to exist in different oxidation states
  • the size of the metal atoms
  • the number of empty atomic orbitals available
  • none of these
Match the catalysts to the correct processes:

Catalyst                             Process
A. $$TiCl_3$$i. Wacker process
B. $$PdCl_2$$ii. Ziegler - Natta polymerization
C. $$CuCl_2$$iii. Contact process
D. $$V_2O_5$$iv. Deacon's process
  • (A) - (iii), (B) - (ii), (C) - (iv), (D) - (i)
  • (A) - (ii), (B) - (i), (C) - (iv), (D) - (iii)
  • (A) - (ii), (B) - (iii), (C) - (iv), (D) - (i)
  • (A) - (iii), (B) - (i), (C) - (ii), (D) - (iv)
Which of the following statement(s) is (are) not correct with reference to ferrous and ferric ions?
  • $$Fe^{3+}$$ gives brown colour with potassium ferricyanide
  • $$Fe^{2+}$$ gives blue ppt with potassium ferricyanide
  • $$Fe^{3+}$$ gives red colour with potassium sulphocyanide
  • $$Fe^{2+}$$ gives brown colour with potassium sulphocyanide
Which of the following ion involved in the above process will show paramagnetism? 
  • $$V^{5+}$$
  • $$V^{4+}$$
  • $$O^{2-}$$
  • $$VO_3^-$$
The bivalent metal ion having maximum paramagnetic behaviour among the first transition series elements is :
  • $$Mn^{2+}$$
  • $$Cu^{2+}$$
  • $$Sc^{2+}$$
  • $$Cu^+$$
Statement 1 : A piece of zinc placed in a blue copper nitrate solution will displace the copper from the solution, producing copper metal and a colorless $$\displaystyle { Zn }^{ 2+ }$$ solution.
Statement 2 : Copper is a much more active metal than zinc.

  • Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.

  • Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.

  • Statement 1 is correct but Statement 2 is not correct.

  • Statement 1 is not correct but Statement 2 is correct.

  • Both the Statement 1 and Statement 2 are not correct.


The electrical conductivity of copper is due to which of the following?
  • Hydrogen bonding
  • Ionic bonding
  • Network bonding
  • London dispersion force
  • Metallic bonding
Potassium maganate $$ (K_2MnO_4) $$ is formed when:
  • Chlorine is passed into aqueous $$ KMnO_4 $$ solution
  • Manganese dioxide is fused with potassium hydroxide in air
  • Formaldehyde reacts with potassium permanganate in the presence of a strong alkali
  • Potassium permanganate reacts with concentrated sulphuric acid.
Identify the order in which the spin only magnetic moment (in BM) increases for the following four ions:
(I) $$Fe^{2+}$$ (II) $$Ti^{2+}$$ (III) $$Cu^{2+}$$ (IV) $$V^{2+}$$
  • $$I, II, IV, III$$
  • $$IV, I, II, III$$
  • $$III, IV, I, II$$
  • $$III, II, IV, I$$
Statement 1: Transition metal compounds generally exhibit bright colors.
Statement 2: The electrons in the partially filled d orbitals are easily promoted to excited states.

  • Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.

  • Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.

  • Statement 1 is correct but Statement 2 is not correct.

  • Statement 1 is not correct but Statement 2 is correct.

  • Both the Statement1 and Statement 2 are not correct.
The compound pictured below undergoes decomposition when heated.
Which of the following CORRECTLY represents a possible set of products of this decomposition?
528711_7850b9d1617541719015a13dc7688258.png
When $$MnO_2$$ is fused with $$KOH$$ and $$KNO_3$$, a coloured compound is formed, the product and its colour is:
  • $$K_2MnO_4, $$ Green
  • $$KMnO_4,$$ Purple
  • $$Mn_2O_3, $$ Blue
  • $$K_3MnO_2$$, Red
In the oxidation of oxalic acid by potassium permanganate, in the presence of dil. $$H_2SO_4$$ one of the products _______ acts as an autocatalyst.
  • $$K_2SO_4$$
  • $$MnSO_4$$
  • $$MnO_2$$
  • $$Mn_2O_3$$
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