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NEET CHEMISTRYThe d-and f-Block ElementsEasy

Question

The catalytic activity of transition metals is due to:

A

High enthalpy of atomization

B

Paramagnetic behaviour

C

Colour of hydrated ions

D

Variable oxidation states

Step-by-Step Solution

The transition metals and their compounds are well known for their catalytic activity. This activity is primarily ascribed to their ability to adopt multiple (variable) oxidation states and to form complexes . Because they can change their oxidation states, they easily form unstable intermediate compounds with reactants, providing an alternate reaction pathway with lower activation energy.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from The d-and f-Block Elements. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYThe d-and f-Block Elementscatalyticactivitytransitionmetals

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The $E^\circ$ value for the $Mn^{3+}/Mn^{2+}$ couple is more positive than that of $Cr^{3+}/Cr^{2+}$ or $Fe^{3+}/Fe^{2+}$ due to change of:

A.$d^5$ to $d^2$ configuration
B.$d^4$ to $d^5$ configuration
C.$d^3$ to $d^5$ configuration
D.$d^5$ to $d^4$ configuration
MediumSolve

The manganate and permanganate ions are tetrahedral, due to:

A.The π-bonding involves the overlap of d-orbitals of oxygen with d-orbitals of manganese.
B.The π-bonding involves the overlap of p-orbitals of oxygen with d-orbitals of manganese.
C.Absence of π-bonding.
D.The π-bonding involves the overlap of p-orbitals of oxygen with p-orbitals of manganese.
MediumSolve

The incorrect statement among the following is:

A.Lanthanoids are good conductors of heat and electricity.
B.Actinoids are highly reactive metals, especially when finely divided.
C.Actinoid contraction is greater for element to element than Lanthanoid contraction.
D.Most of the trivalent Lanthanoid ions are colourless in the solid-state.
MediumSolve

When neutral or faintly alkaline $KMnO_4$ is treated with potassium iodide, iodide ion is converted into 'X'. 'X' is:

A.$I_2$
B.$IO_4^-$
C.$IO_3^-$
D.$IO^-$
MediumSolve

Identify the incorrect statement among the following:

A.There is a decrease in the radii of the atoms or ions as one proceeds from $\text{La}$ to $\text{Lu}$.
B.Lanthanoid contraction is the accumulation of successive shrinkages.
C.As a result of lanthanoid contraction, the properties of 4d series of the transition elements have no similarities with the 5d series of elements.
D.Shielding power of 4f electrons is quite weak.
MediumSolve

Acidified $K_2Cr_2O_7$ solution turns green when $Na_2SO_3$ is added to it. This is due to the formation of:

A.$CrO_4^{2-}$
B.$Cr_2(SO_3)_3$
C.$CrSO_4$
D.$Cr_2(SO_4)_3$
MediumSolve

Which of the following ions will exhibit colour in aqueous solutions?

A.$La^{3+} (Z=57)$
B.$Ti^{3+} (Z=22)$
C.$Lu^{3+} (Z=71)$
D.$Sc^{3+} (Z=21)$
EasySolve

Which of the following ions displays the d-d transition and paramagnetism?

A.$\text{CrO}_4^{2-}$
B.$\text{Cr}_2\text{O}_7^{2-}$
C.$\text{MnO}_4^-$
D.$\text{MnO}_4^{2-}$
MediumSolve

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