The d and f Block Elements
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47. 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 stabilizes lower oxidation state
(D) In covalent compounds fluorine can form single bond only while oxygen forms double bond
47. 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 stabilizes lower oxidation state
(D) In covalent compounds fluorine can form single bond only while oxygen forms double bond
47. (D) in covalent compounds fluorine can form single bond only while oxygen forms double bond
Oxygen has the capacity to form multiple bonds which enables it to form a variety of covalent compounds.
In (Mn2O7) also, 6 oxygen are doubly bonded to two manganese atoms and one oxygen is for
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46. When acidified K2Cr2O7 solution is added to Sn2+ salts Sn2+ changes to
(A) Sn
(B) Sn3+
(C) Sn4+
(D) Sn+
46. When acidified K2Cr2O7 solution is added to Sn2+ salts Sn2+ changes to
(A) Sn
(B) Sn3+
(C) Sn4+
(D) Sn+
46. (C) Sn4+
Cr2O72- + 14H+ + 3Sn2+ → 2Cr3 + + 3Sn4+ + 7H2O
In the above redox reaction, oxidation of Sn2+ is taking place. It gets converted to Sn4+ whereas, reduction of chromium is occurring
Upvote 45. 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 oxidizing agents in aqueous solution
(D) Ti2+ and Cr2+ a re reducing agents in aqueous solution
45. 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 oxidizing agents in aqueous solution
(D) Ti2+ and Cr2+ a re reducing agents in aqueous solution
45. (A) is incorrect.
Copper lies below hydrogen in electrochemical series and hence cannot liberate hydrogen from acids.
Cu + 2H2SO4 → CuSO4 + SO2 + 2H2O
Upvote 44. KmNO4 acts as an oxidizing agent in alkaline medium. When alkaline KmNO4 is treated with KI, iodide ion is oxidized to
(A) I2
(B) IO−
(C) IO3−
(D) IO4−
44. KmNO4 acts as an oxidizing agent in alkaline medium. When alkaline KmNO4 is treated with KI, iodide ion is oxidized to
(A) I2
(B) IO−
(C) IO3−
(D) IO4−
44. (C) IO3-
Iodide is oxidised to iodate.
2KMnO4 + KI + H2O → 2KOH + 2MnO2 + KIO3
iodide
Upvote 43. 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.
43. 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.
43. (B) 3.87 B.M.
Cr → (Z = 24)
Cr3 + → (Z = 21)
1s2 2s2 2p6 3s2 3p6 3d3 4s0
n = 3 ( 3 unpaired electrons )
μ =
μ =
μ =
μ =
= 3.87 B.M.
Upvote 42. 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.
42. 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.
42. (D) They are chemically very reactive.
Interstitial compounds/alloys are substances that are formed when a small atom like carbon, hydrogen, boron, nitrogen can occupy space in their lattices. All the properties mentioned above are true for interstitial compounds except (D), they are chemic
Upvote 41. Gadolinium belongs to the 4f series. Its atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
(A) [Xe] 4f7 5d1 6s2
(B) [Xe] 4f6 5d2 6s2
(C) [Xe] 4f8 6d2
(D) [Xe] 4f9 5s1
41. Gadolinium belongs to the 4f series. Its atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
(A) [Xe] 4f7 5d1 6s2
(B) [Xe] 4f6 5d2 6s2
(C) [Xe] 4f8 6d2
(D) [Xe] 4f9 5s1
41. (A) [Xe] 4f7 5d1 6s2
Gadolinium belongs to the 4f series; it has atomic no.= 64. It has extra stability due to a half-filled 4f subshell.
Gd (Z=64) ? [Xe] 4f6 5d2 6s2
Upvote 40. 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
40. 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
40. (A) V2O5, Cr2O3
Oxides in the lower oxidation state are basic and in the higher oxidation state they are acidic. They are amphoteric in the intermediate oxidation state. Therefore, V2O5, Cr2O3 are amphoteric in nature.
Upvote 11. KMnO4 acts as an oxidizing 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) 25
(B) 35
(C) 45
(D) 15
11. KMnO4 acts as an oxidizing 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) 25
(B) 35
(C) 45
(D) 15
39. (A) 25
2MnO4- + 5S2- + 16H+ → 2Mn2+ + 5S + H2O
From the reaction,
For 5 moles of S, two moles of KMnO4 were required.
Therefore, for one mole of S, the number of moles of KMnO4 required will be = 25.
Upvote 38. There are 14 elements in the actinide series. Which of the following elements does-not belong to this series?
(A) U
(B) Np
(C) Tm
(D) Fm
38. There are 14 elements in the actinide series. Which of the following elements does-not belong to this series?
(A) U
(B) Np
(C) Tm
(D) Fm
38. (C) Tm
In the periodic table, actinides lie from atomic number 90 to 103.
Thulium is not an actinide; it is a lanthanide.
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