1
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
In which one of the following pairs does the stability of the monovalent ion increase with respect to the molecule, while the magnetic character remains the same for both?
A
$\mathrm{C}_2 / \mathrm{C}_2^{+}$
B
$\mathrm{O}_2 / \mathrm{O}_2{ }^{+}$
C
$\mathrm{B}_2 / \mathrm{B}_2{ }^{+}$
D
$\mathrm{N}_2 / \mathrm{N}_2^{+}$
2
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
When $9.2 \times 10^{-3} \mathrm{~kg}$ of formic acid is added to 600 ml of water the freezing point of water is depressed. If $30 \%$ of Formic acid undergoes dissociation what would be the freezing point of the solution? ( $\mathrm{K}_{\mathrm{f}}$ of $\mathrm{H}_2 \mathrm{O}$ is 1.86 K kg mol ; MM of formic acid: 46 amu )
A
273.9 K
B
272.2 K
C
270.1 K
D
270.8 K
3
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
An organic compound $[\mathrm{X}]$ (molecular formula- $\mathrm{C}_5 \mathrm{H}_{11} \mathrm{NO}$ when reacted with $\mathrm{Br}_2$ / aq. NaOH yielded $[\mathrm{Y}]$ which reacts with $\mathrm{CHCl}_3$ and Ethanolic KOH to produce a foul smelling compound. Compound $[\mathrm{Y}]$ also reacts with HONO to produce Butan-1-ol with liberation of $\mathrm{N}_2(\mathrm{~g})$. Identify [X].
A
$\mathrm{CH}_3-\left(\mathrm{CH}_2\right)_3-\mathrm{CONH}_2$
B
$\mathrm{CH}_3-\left(\mathrm{CH}_2\right)_2-\mathrm{CO}-\mathrm{CH}_2-\mathrm{NH}_2$
C
$\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CO}-\left(\mathrm{CH}_2\right)_2-\mathrm{NH}_2$
D
$\mathrm{CH}_3-\left(\mathrm{CH}_2\right)_2-\mathrm{CH}\left(\mathrm{NH}_2\right)-\mathrm{CHO}$
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
Choose the correct statement.
A
Ionic compounds of $\mathrm{Sc}^{3+}$ and $\mathrm{Cu}^{+}$are coloured because of $\mathrm{d}-\mathrm{d}$ electronic transitions
B
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 $\mathrm{V}^{2+}<\mathrm{Cr}^{2+}=\mathrm{Mn}^{2+}<\mathrm{Fe}^{2+}$
C
As the oxidation number of the transition element increases, the ionic nature decreases and the oxides show acidic nature predominantly
D
The metal Cobalt has the electronic configuration $[\mathrm{Ar}] 3 \mathrm{~d}^5$ in the +3 oxidation state
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