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Class 12 Chemistry Chapter 8 the d and f Block Elements MCQs | Class 12 Chemistry Chapter 8 the d and f Block Elements Objective Type Questions and Answers

(1) Which of general symbol is used to represent Lanthanoides ?
[A] Ln
[B] La
[C] Le
[D] Li
Answer: Ln
(2) Which of following elements are include in actinide ?
[A] Th to Lr
[B] Ac to Lr
[C] Ac to No
[D] Th to No
Answer: Th to Lr
(3) Which of following radioactive elements in Lanthanodies.
[A] Promethium (Pm)
[B] Lutetium (Lu)
[C] Yetterbium (Yb)
[D] Samarium (Sm)
Answer: Promethium (Pm)
(4) Which of following is used in gas lighters ?
[A] CeO2
[B] Pyrophoric Misch metal
[C] Gadolinium sulphate
[D] Ceric compounds
Answer: Pyrophoric Misch metal
(5) Which of following is used as oxidizing agent in volumetric analysis ?
[A] Ceric compounds
[B] CeO2
[C] Oxides of lanthanoids
[D] Gadolinium sulphate
Answer: Ceric compounds
(6) Which of following is used in preparation of optical glass of camera having high refractive index ?
[A] ceric compounds
[B] CeO2
[C] Oxides of lanthanoids
[D] Gadolinium sulphate
Answer: Oxides of lanthanoids
(7) Which of following is used to produce very low temperature by magnetic field ?
[A] Pyrophoric misch metal
[B] Uranium
[C] Thorium
[D] Gadolinium sulphate
Answer: Gadolinium sulphate
(8) What is the constitution of metals in pyrophoric misch metal ?
[A] ce-50%, ca-40%, Fe-10%
[B] Ce-50%, La-40%, Fe-7%, other-5%
[C] Ce-40%, La-50%, Fe-5%, other-5%
[D] Ce-40%, La-50%, Fe-10%
Answer: Ce-50%, La-40%, Fe-7%, other-5%
(9) Which of following statement is wrong ?
[A] Atoms of all transition elements are paramagnetic
[B] All transition elements are metals
[C] All elements of d-block are transition elements
[D] D-block elements are present in between s & p block elements in periodic table
Answer: Atoms of all transition elements are paramagnetic
(10) Why do theoritical value of magnetic moment differ from their practical value ?
[A] Due to decrease in volume of metal ion
[B] Due to unsymmetrical arrangement of dipoles in orbital
[C] Due to rotation-orbital combination
[D] Both are different methods to calculate magnetic moment
Answer: Due to rotation-orbital combination
(11) What is the value of magnetic moment of central metal ion in K2MnO4 ?
[A] 0.0 BM
[B] 1.73 BM
[C] 2.83 BB
[D] 3.87 BM
Answer: 1.73 BM
(12) What will be obtained when managanese dioxide is fused with KOH in presence of oxidizing agent like KNO3 ? What will be the colour of product ? 
[A] K2 MnO4 Dark green
[B] KMnO4, Violet
[C] Mn2O3, Grey
[D] Mn2O4, Black
Answer: K2 MnO4 Dark green
(13) Which of following group of transition metal is used to prepare currency coins ?
[A] Cu, Ag, Au
[B] Ru, Rh, Pd
[C] Fe, Co, Ni
[D] Os, Ir, Pt
Answer: Cu, Ag, Au
(14) Ce is an important member of Lanthenoid series which of following is wrong statement for Ce ?
[A] The general oxidation state of Ce is +3 and +4
[B] +3 oxidation state of Ce is more stable than +4
[C] +4 oxidation state of Ce is not available in its aqueous solution
[D] Ce (IV) behave as oxidizing agent
Answer: The general oxidation state of Ce is +3 and +4
(15) Lanthanide contraction is caused due to ____
[A] The appreciable shilding on outer electrons by 4f electrons from the nuclear charge
[B] The appreciable shilding on outer electrons by 5d electrons from the nuclear charge
[C] The same effective nuclear charge from Ce to Lu
[D] The poor shilding on outer electrons by 4f electrons from the nucluear charge
Answer: The poor shilding on outer electrons by 4f electrons from the nucluear charge
(16) The actinides exhibit more number of oxidation states in general than the lanthanide, because ____
[A] The 5f-orbitals are more spread in place than the 4f orbitals
[B] Energy differnce between 5f and 6d orbitals is less than that of 4f and 5d orbitals
[C] Energy difference between 5f and 6d orbital is more than that of 4f and 5d orbitals
[D] Actinides are more reactive than that of lanthanides
Answer: Energy differnce between 5f and 6d orbitals is less than that of 4f and 5d orbitals
(17) The general oxidation state of Lanthanide elements is +3. Which of following is incorrect statement for them ?
[A] Ln (III) hydroxides are mainly basic in character
[B] Because of the large size of the Ln (III) ions, the bonding in its compounds is ionic in character
[C] Ln (III) Compounds are generally colourless
[D] The ionic sizes of Ln (III) decreases with increase in atomic number
Answer: Because of the large size of the Ln (III) ions, the bonding in its compounds is ionic in character
(18) Which of following statement is wrong for transition element ?
[A] Once the d5 configuration nis exceeded the tendency to involve all the 3d electrons in bonding decreases
[B] In addition to the normal oxidation states, the zero oxidation state is also shown by these elements in complexes
[C] In the highest oxidation states, the transition metals show basic
[D] In the highest oxidation states of the first five (transition elements (Sc to Mn) all the 4s & 3d electrons are used for bonding
Answer: In the highest oxidation states, the transition metals show basic
(19) Which of following is wrong statement ?
[A] La (OH)3 is less basic than Lu(OH)3
[B] In lanthanide series, ionic radius decreases while moving Ce3+ to Lu3+ ion
[C] La is actually tranusition element
[D] Due to Lanthanide contraction atomic radius of Zn and Hf are same
Answer: La (OH)3 is less basic than Lu(OH)3
(20) What is oxidation no. of Cr in K2 Cr2 O7
[A] +2
[B] +4
[C] +6
[D] +7
Answer: +2

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