COMEDK 2025 Morning Shift | d and f Block Elements Question 9 | Chemistry

The order in which the paramagnetic nature of the 4 cations $\mathrm{Cr}^{2+}, \mathrm{Mn}^{2+}, \mathrm{V}^{2+}$ and $\mathrm{Fe}^{2+}$ vary is $\mathrm{V}^{2+}<\mathrm{Cr}^{2+}=\mathrm{Mn}^{2+}<\mathrm{Fe}^{2+}$

As the oxidation number of the transition element increases, the ionic nature decreases and the oxides show acidic nature predominantly

The metal Cobalt has the electronic configuration $[\mathrm{Ar}] 3 \mathrm{~d}^5$ in the +3 oxidation state

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

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COMEDK 2025 Morning Shift Chemistry - d and f Block Elements Question 8 English

What is the spin only magnetic moment of the metal ion in $\mathbf{P}$ and the oxidation number of Sulphur in the oxidised product Z ?

$\mu=0 \quad$ Oxidation number $=+4$

$\mu=5.00 \mathrm{BM} \quad$ Oxidation number $=0$

$\mu=5.92 \mathrm{BM} \quad$ Oxidation number $=+2$

$\mu=1.732 \mathrm{BM} \quad$ Oxidation number $=+6$

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

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Identify the correct statement from the following.

The green manganate ion shows diamagnetic nature but the permanganate ion exhibits paramagnetic nature

Interstitial compounds of transition metals have lower melting points than that of pure transition metals and their compounds are chemically reactive

Cerium is a lanthanoid metal which exists in a stable oxidation state of +4 , besides exhibiting an oxidation state of +3

$$\mathrm{Cr}(\mathrm{VI})$$ is more stable than $$\mathrm{W}(\mathrm{VI})$$ and hence acts as a good oxidising agent

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

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An inorganic compound $$\mathrm{W}$$ undergoes the following reactions:

$$ \begin{gathered} W+\frac{\mathrm{Na}_2 \mathrm{CO}_3}{\mathrm{O}_2 / \text { heat }} \rightarrow X+\frac{\mathrm{H}^{+}}{} \rightarrow Y_{(s)} \\ Y(a q)+\mathrm{KCl}(\mathrm{aq}) \rightarrow Z_{(S)} \end{gathered} $$

Z appears in the form of orange crystals and is used as an oxidising agent in acid medium. Identify the compound W.

$$\mathrm{K}_2 \mathrm{CrO}_4$$

$$\mathrm{FeCr}_2 \mathrm{O}_4$$

$$\mathrm{Cu}(\mathrm{CrO}_2)_2$$

$$\mathrm{Na}_2 \mathrm{CrO}_4$$

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