AIIMS Chemistry The D And Fblock Elements Class 12 Questions

Which of the following exhibit minimum number of oxidation states :

In the equation, $$4\text{M} + 8\text{CN}^- + 2\text{H}_2\text{O} + \text{O}_2 \rightarrow 4[\text{M}(\text{CN})_2]^- + 4\text{OH}^-$$ Identify the metal (M)

In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct answer out of the following choice. Assertion (A) $\text{Pb}^{4+}$ compounds are stronger oxidising agents than Sn $\text{Pb}^{4+}$ compounds. Reason (R) The higher oxidation state for group-14 elements are more stable for the heavier members of the group due to inert pair effect.

For which of the following elements it is difficult to disproportionate in +3 oxidation state?

Which is not stable under ambient condition?

Assertion: $\text{Ce}^{4+}$ is used as an oxidising agent in volumetric analysis. Reason: $\text{Ce}^{4+}$ has the tendency of attaining +3 oxidation state.

Assertion: $\text{La}(\text{OH})_3$ is more basic than $\text{Lu}(\text{OH})_3$. Reason: Size of $\text{Lu}^{3+}$ increases and shows more covalent character.

What are constituents of 'Mischmetal'?

Assertion: Transition metals are poor reducing agents. Reason: Transition metals form numerous alloys with other metals.

Which of the element shows +4 oxidation state?

Assertion : Magnetic moment of Dy is the highest among the lanthanoids. Reason : Orbital motion contributes magnetic moment.

Given below, catalyst and corresponding process/reaction are matched. The mismatch is

Assertion : K₂Cr₂O₇ is used as primary standard in volumetric analysis. Reason : It has a good solubility in water.

Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other, in

Assertion : The free gaseous Cr atom has six unpaired electrons. Reason : Half-filled s orbital has greater stability.

The colourless species is

Lanthanide for which +II and +III oxidation states are common is

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

Which of the following has highest second ionization energy?

Which of the following is the correct sequence of atomic weights of the given elements ?

In dichromate dimer

Assertion: Pb⁴⁺ can be reduced easily to Pb²⁺. Reason: Pb2+ is paramagnetic.