1
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Identify the correct statement from the following.

A
The green manganate ion shows diamagnetic nature but the permanganate ion exhibits paramagnetic nature
B
Interstitial compounds of transition metals have lower melting points than that of pure transition metals and their compounds are chemically reactive
C
Cerium is a lanthanoid metal which exists in a stable oxidation state of +4 , besides exhibiting an oxidation state of +3
D
$$\mathrm{Cr}(\mathrm{VI})$$ is more stable than $$\mathrm{W}(\mathrm{VI})$$ and hence acts as a good oxidising agent
2
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

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.

A
$$\mathrm{K}_2 \mathrm{CrO}_4$$
B
$$\mathrm{FeCr}_2 \mathrm{O}_4$$
C
$$\mathrm{Cu}(\mathrm{CrO}_2)_2$$
D
$$\mathrm{Na}_2 \mathrm{CrO}_4$$
3
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

The Lanthanoid ion which would form coloured compounds is -------------.

Atomic numbers: $$\mathrm{Yb}=70, \quad \mathrm{Lu}=71, \mathrm{Pr}=59, \quad \mathrm{La}=57$$

A
$$Y b^{2+}$$
B
$$L a^{3+}$$
C
$$L u^{3+}$$
D
$$\operatorname{Pr}^{3+}$$
4
COMEDK 2024 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Arrange the following ions in the increasing order of their $$\Delta H_{(\text {hydration})}$$ values.

$$\mathrm{Cr}^{2+}, \mathrm{Co}^{2+}, \mathrm{Mn}^{2+}, \mathrm{Ni}^{2+}$$

A
$$ \mathrm{Co}^{2+}<\mathrm{Ni}^{2+}<\mathrm{Cr}^{2+}<\mathrm{Mn}^{2+} $$
B
$$ \mathrm{Cr}^{2+}<\mathrm{Mn}^{2+}<\mathrm{Co}^{2+}<\mathrm{Ni}^{2+} $$
C
$$ \mathrm{Ni}^{2+}<\mathrm{Co}^{2+}<\mathrm{Mn}^{2+}<\mathrm{Cr}^{2+} $$
D
$$ \mathrm{Mn}^{2+}<\mathrm{Cr}^{2+}<\mathrm{Co}^{2+}<\mathrm{Ni}^{2+} $$
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