Explain briefly the cause of Lanthanoid contraction. from Chemis

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 Multiple Choice QuestionsMultiple Choice Questions

321.

The electronic configuration of Cu is

  • [Ne] 3s2, 3p6, 3d9, 4s2

  • [Ne] 3s2, 3p6, 3d10, 4s1

  • [Ne] 3s2, 3p6, 3d3, 3d9, 4s2, 4p6

  • [Ne] 3s2, 3p6, 3d5, 4s2, 4p4


322.

Assertion: Cuprous ion (Cu+) is colorless whereas cupric ion (Cu2+) is blue in the aqueous solution.
Reason: Cuprous ion (Cu+) has unpaired electrons while cupric ion (Cu2+) does not.

  • If both assertion and reason are true and reason is a correct explanation of the assertion.

  • If both the assertion and reason are true but the reason is not a correct explanation of the assertion.

  • If the assertion is true but the reason is false.

  • If both the assertion and reason are false.


323.

The stable bivalency of Pb and trivalencey of Bi is:

  • due to d contraction in Pb and Bi

  • due to relativistic contraction of the 6s orbitals of Pb and Bi, leading to inert pair effect

  • due to screening effect

  • due to the attainment of noble liquid configuration


324.

A magnetic moment of 1.73 BM will be shown by one among the following

  • [Cu(NH3)4]2+

  • [Ni(CN)4]2-

  • TiCl4

  • [CoCl6]4-


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325.

Which of the following does not give oxygen on heating?

  • KClO3

  • Zn(ClO3)2

  • K2Cr2O7

  • (NH4)2Cr2O7


326.

Which ofthe following lanthanoid ions is diamagnetic?
(At. nos. Ce = 58, Sm = 62, Eu = 63, Yb= 70)

  • Ce2+

  • Sm2+

  • Eu2+

  • Yb2+


327.

Platinum, palladium and iridium are called noble metals because:

  • Alfred Nobel discovered them

  • they are shining lustrous and pleasing to look at

  • they are found in native state

  • they are inert towards many common reagents


328.

Cupric compounds are more stable than their cuprous counterparts in solid state. This is because

  • the endothermic character of the 2nd IP of Cu is not so high

  • size of Cu2+ is less than Cu+

  • Cu2+ has stable electronic configuration as compared to Cu+

  • the lattice energy released for cupric compounds is much higher than Cu+


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 Multiple Choice QuestionsShort Answer Type

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329.

Explain briefly the cause of Lanthanoid contraction.


On moving in the lanthanoid series from left to right successive electrons enter into ante penultimate 4f-subshell which imparts very poor shielding effect (due to its diffused nature), hence effective nuclear charge gradually increases with increase in atomic number. That is why shrinkage is observed on moving through lanthanide series, this is known as lanthanide contraction.


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 Multiple Choice QuestionsMultiple Choice Questions

330.

Anhydrous ferric chloride is prepared by:

  • dissoving Fe(OH)3 in concentrated HCl

  • dissolving Fe(OH)3 in dilute HCl

  • passing dry HCl overheated iron scrap

  • passing dry Cl2 gas overheated iron scrap


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