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

Consider the following statements in respect of lanthanides, which of the statements are incorrect?

(i) $$\mathrm{La}(\mathrm{OH})_3$$ is least basic among the hydroxides of lanthanides

(ii) The lanthanide ions $$\mathrm{Yb}^{2+}, \mathrm{Lu}^{3+}$$ and $$\mathrm{Ce}^{4+}$$ are diamagnetic in nature.

(iii) $$\mathrm{Ce}^{4+}$$ can act as an oxidising agent

(iv) $$\operatorname{Ln}$$ (III) compounds are generally colourless

(v) Ionic radii of $$\mathrm{Ce}^{3+}$$ is greater than $$\mathrm{Yb}^{3+}$$

A
(i), (ii) and (iii)
B
(i) and (iv)
C
(iii), (iv) and (v)
D
(iii) and (iv)
2
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
$$ \mathrm{Mn}^{2+}<\mathrm{Cr}^{2+}<\mathrm{Co}^{2+}<\mathrm{Ni}^{2+} $$
3
COMEDK 2024 Morning Shift
MCQ (Single Correct Answer)
+1
-0

The permanganate ion in acid medium acts as an oxidant and gets converted to its lower oxidation state. What would be the spin only magnetic moment of such reduced manganese ion?

A
2.84 BM
B
4.90 BM
C
3.87 BM
D
5.92 BM
4
COMEDK 2024 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Match the compounds given in Column I with their characteristic features listed in Column II

No. Column I No. Column II
A $$
\mathrm{La}(\mathrm{OH})_3
$$
P Acidic in nature
B $$
\mathrm{Mn}_2 \mathrm{O}_7
$$
Q Least basic
C $$
\mathrm{Lu}(\mathrm{OH}) 3
$$
R Interstitial compound
D $$
\mathrm{Fe}_3 \mathrm{H}
$$
S Most basic

A
$$ \mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{P} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{R} $$
B
$$ \mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{P} $$
C
$$ \begin{array}{llll} \mathrm{A}=\mathrm{Q} & \mathrm{B}=\mathrm{P} & \mathrm{C}=\mathrm{S} & \mathrm{D}=\mathrm{R} \end{array} $$
D
$$ \begin{array}{llll} \mathrm{A}=\mathrm{R} & \mathrm{B}=\mathrm{P} & \mathrm{C}=\mathrm{S} & \mathrm{D}=\mathrm{Q} \end{array} $$
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