MCQ Questions for Class 12 Chemistry Chapter 8 The d-and f-Block Elements with Answers

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The d-and f-Block Elements Class 12 MCQs Questions with Answers

Solving the The d-and f-Block Elements Multiple Choice Questions of Class 12 Chemistry Chapter 8 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on The d-and f-Block Elements Class 12 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 8 Chemistry Class 12 and cross-check your answers during preparation.

Question 1.
Which transition metal can show highest oxidation state?
(a) Sc
(b) Ti
(c) Os
(d) In

Answer

Answer: (c) Os


Question 2.
Which of the following is not an actinoid?
(a) Thorium
(b) Californium
(c) Uranium
(d) Terbium

Answer

Answer: (d) Terbium


Question 3.
Which of the following would be diamagnetic?
(a) Cu2+
(b) Ni2+
(c) Cd2+
(d) Ti3+

Answer

Answer: (c) Cd2+


Question 4.
Misch metal is an alloy of
(a) La
(b) Th
(c) Ac
(d) none of these

Answer

Answer: (a) La


Question 5.
Maximum magnetic moment is shown by
(a) 3d8
(b) 3d7
(c) 3d9
(d) 3d5

Answer

Answer: (d) 3d5


Question 6.
Maximum oxidation number of manganese is in
(a) K2MnO4
(b) MnO2
(c) KMnO4
(d) Mn2O4

Answer

Answer: (c) KMnO4


Question 7.
Electronic configuration of Fez+ ion is
(a) [Ar] 4s23d4
(b) [Ar] 4s13d5
(c) [Ar] 3d6
(d) [Ar] 3d8

Answer

Answer: (c) [Ar] 3d6


Question 8.
Electronic configuration of Cr (Z = 24) is
(a) 3d4 4s2
(b) 3d6 4s0
(c) 3d5 4s1
(d) none of these

Answer

Answer: (c) 3d5 4s1


Question 9.
Increasing order of paramagnetism is
(a) Cu2+ CO2+, Mn2+, Ni2+
(b) CO2+, Cu2+, Mn2+, Ni2+
(c) Cu2+, Ni2+, CO2+, Mn2+
(d) Mn2+, CO2+, Ni2+, Cu2+

Answer

Answer: (c) Cu2+, Ni2+, CO2+, Mn2+


Question 10.
Copper sulphate dissolves in excess of KCN to give:
(a) [CU(CN)4]3-
(b) [CU(CN)4]2-
(c) CuCN
(d) [Cu(CN2].

Answer

Answer: (a) [CU(CN)4]3-


Question 11.
Which of the following is not a lanthanoid element?
(a) Cerium
(b) Europium
(c) Lutetium
(d) Thorium

Answer

Answer: (d) Thorium


Question 12.
Which is colourless in H2O?
(a) Ti3+
(b) V3+
(c) Cr3+
(d) Sc3+

Answer

Answer: (d) Sc3+


Question 13.
Which one is coloured?
(a) Cu2Cl2
(b) [SC(H2O)6]3+
(c) [Zn(H2O)6]2+
(d) [Ti(H2O)6]3+

Answer

Answer: (d) [Ti(H2O)6]3+


Question 14.
Which of the following titanium compounds cannot be prepared? (Atomic No. of Ti = 22)
(a) TiO
(b) TiO2
(c) K2TiO4
(d) TiCl2

Answer

Answer: (c) K2TiO4


Question 15.
Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d5. What is its atomic number?
(a) 25
(b) 26
(c) 27
(d) 24

Answer

Answer: (b) 26


Question 16.
The electronic configuration of Cu (II) is 3d9 whereas that of Cu (I) is 3d10. Which of the following is correct?
(a) Cu (II) is more stable
(b) Cu (II) is less stable
(c) Cu (I) and Cu (II) are equally stable
(d) Stability of Cu (I) and Cu (II) depends on nature of copper salts

Answer

Answer: (a) Cu (II) is more stable


Question 17.
Metallic radii of some transition elements are given below.
Fe – 126
Co – 125
Ni – 125
Cu – 128
Which of these elements will have highest density?
(a) Fe
(b) Ni
(c) Co
(d) Cu

Answer

Answer: (d) Cu


Question 18.
Generally transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds will be coloured in solid state?
(a) Ag2 SO4
(b) CuF2
(c) ZnF2
(d) Cu2 Cl2

Answer

Answer: (b) CuF2


Question 19.
On addition of small amount of KMnO4 to concentrated H2SO4, a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following.
(a) Mn2O7
(b) MnO2
(c) MnSO4
(d) Mn2O3

Answer

Answer: (a) Mn2O7


Question 20.
The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
(a) 3d7
(b) 3d5
(c) 3d8
(d) 3d2

Answer

Answer: (b) 3d5


Question 21.
Which of the following oxidation state is common for all lanthanoids?
(a) +2
(b) +3
(c) +4
(d) +5

Answer

Answer: (b) +3


Question 22.
Which of the following reactions are disproportionation reactions?
(i) Cu+ → Cu2+ + Cu
(ii) 3MnO42- + 4H+ → 2MnO4 + MnO2 + 2H2O
(iii) 2KMnO4 → K2MnO4 + MnO2 + O2
(iv) 2MnO4 + 3Mn2+ + 2H2O → 5MnO2 + 4H+
(a) i, ii
(b) i, ii, iii
(c) ii, iii, iv
(d) i, iv

Answer

Answer: (a) i, ii


Question 23.
When KMnO4 solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because
(a) CO2 is formed as the product
(b) Reaction is exothermic
(c) MnO4 catalyses the reaction
(d) Mn2+ acts as autocatalyst

Answer

Answer: (d) Mn2+ acts as autocatalyst


Question 24.
There are 14 elements in actinoid series. Which of the following elements does not belong to this series?
(a) U
(b) Np
(c) Tm
(d) Fm

Answer

Answer: (c) Tm


Question 25.
KMnO4 acts as an oxidising agent in acidic medium. The number of moles of KMnO4 that will be needed to react with one mole of sulphide ions in acidic solution is
(a) 2/5
(b) 3/5
(c) 4/5
(d) 1/5

Answer

Answer: (a) 2/5


Question 26.
Which of the following is amphoteric oxide?
Mn2O7, CrO3, Cr2O3, CrO, V2O5, V2O4
(a) V2O5, Cr2O3
(b) Mn2O7, CrO3
(c) CrO, V2O5
(d) V2O5, V2O4

Answer

Answer: (a) V2O5, Cr2O3


Question 27.
Gadolinium belongs to 4f series. Its atomic number is 64.
Which of the following is the correct electronic configuration of gadolinium?
(a) [Xe] Af7 5d16s²
(b) [Xe] 4f6 5d² 6s²
(c) [Xe] 4f8 6d²
(d) [Xe]4f9 5s1

Answer

Answer: (a) [Xe] Af7 5d16s²


Question 28.
Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds?
(a) They have high melting points in comparison to pure metals
(b) They are very hard
(c) They retain metallic conductivity
(d) They are chemically very reactive

Answer

Answer: (d) They are chemically very reactive


Question 29.
The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr3+ ion is
(a) 2.87 B.M.
(b) 3.87 B.M.
(c) 3.47 B.M.
(d) 3.57 B.M.

Answer

Answer: (b) 3.87 B.M.


Question 30.
KMnO4 acts as an oxidising agent in alkaline medium.
When alkaline KMnO4 is treated with Kl, iodide ion is oxidised to
(a) l2
(b) lO
(c) lO3
(d) lO4

Answer

Answer: (c) lO3


Question 31.
Which of the following statements is not correct?
(a) Copper liberates hydrogen from acids.
(b) In its higher oxidation states, manganese forms stable compounds with oxygen and fluorine.
(c) Mn3+ and Co3+ are oxidising agents in aqueous solution.
(d) Ti2+ and Cr2+ are reducing agents in aqueous solution.

Answer

Answer: (a) Copper liberates hydrogen from acids.


Question 32.
When acidified K2Cr2O7 solution is added to Sn2+ salts then Sn2+ changes to
(a) Sn
(b) Sn3+
(c) Sn4+
(d) Sn+

Answer

Answer: (c) Sn4+


Question 33.
Highest oxidation state of manganese in fluoride is +4 (MnF4) but highest oxidation state in oxides is +7 (Mn2O7) because
(a) fluorine is more electronegative than oxygen.
(b) fluorine does not possess d-orbitals.
(c) fluorine stabilises lower oxidation state.
(d) in covalent compounds fluorine can form single bond only while oxygen forms double bond.

Answer

Answer: (d) in covalent compounds fluorine can form single bond only while oxygen forms double bond.


Question 34.
Although Zirconium belongs to 4d transition series and Hafnium to 5d transition series even then they show similar physical and chemical properties because
(a) both belong to d-block
(b) both have same number of electrons
(c) both have similar atomic radius
(d) both belong to the same group of the periodic table

Answer

Answer: (c) both have similar atomic radius


Question 35.
Why is HCI not used to make the medium acidic in oxidation reactions of KMnO4 in acidic medium?
(a) Both HCl and KMnO4 act as oxidising agents.
(b) KMnO4 oxidises HCl into Cl2 which is also an oxidising agent.
(c) KMnO4 is a weaker oxidising agent than HCl.
(d) KMnO4 acts as a reducing agent in the presence of HCl.

Answer

Answer: (b) KMnO4 oxidises HCl into Cl2 which is also an oxidising agent.


Assertion and Reason Type Questions

The questions given below consist of an assertion and a reason. Use the following key to choose the appropriate answer.
(a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
(b) Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A)
(c) Assertion (A) is correct, Reason (R) is wrong statement.
(d) Assertion (A) is wrong, but Reason (R) is correct statement.

Question 36.
Assertion: Tungsten has very high melting point.
Reason: Tungsten is a covalent compound.

Answer

Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.


Question 37.
Assertion: Cuprous salts are diamagnetic.
Reason: Cu+ has 3d-filled subshell.

Answer

Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).


Question 38.
Assertion: Fe2+ has 3d6 electronic configuration.
Reason: Electrons are lost from 4s-orbital to form Fe2+ ion.

Answer

Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).


Question 39.
Assertion: La(OH)3 is more basic than LU(OH)3.
Reason: Basic character of hydroxides of lanthanoids increase on moving from La3+ to LU3+.

Answer

Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.


Question 40.
Assertion: FeCl3 reacts with KCNS to give blood red colouration.
Reason: FeCl3 reacts with KCNS to form potassium ferro-ferricyanide.

Answer

Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.


Question 41.
Assertion: Sodium chloride used to clear snow on the roads.
Reason: The alkaline solution of potassium dichromate contains CrO42- ions.

Answer

Answer: (b) Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A)


Question 42.
Assertion: Zn2+ is colourless and Cu2+ is colourled.
Reason: Both Zn2+ and Cu2+ contain 3d-filled subshell.

Answer

Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.


Question 43.
Assertion: There is a continuous decrease in size among lanthanoids.
Reason: Lanthanoids show lanthanoid contraction.

Answer

Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).


Question 44.
Assertion: Lanthanoids show a limited number of oxidation states whereas actinoids show a large number of oxidation states. Reason: Energy gap between 4f, 5d and 6s subshells is small whereas that between 5f, 6d and 7s subshells is large.

Answer

Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.


Question 45.
Assertion: E° value of Mn3+|Mn2+ is more positive than for Cr3+|Cr2+.
Reason: Cr3+ is more stable than Cr2+ but Mn3+ is less stable than Mn2+.

Answer

Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).


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