1
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
The ionisation constant of the weak acid HF whose concentration is 0.1 M is $3.5 \times 10^{-4}$ The Equilibrium constant value for the reaction $\mathrm{F}^{-}+\mathrm{H}_2 \mathrm{O} \leftrightharpoons \mathrm{HF}+\mathrm{OH}^{-}$is _________ and the pH of aqueous solution of the weak acid is __________ .
A
$\mathrm{K}_{\mathrm{eq}}=4.4 \times 10^{-11} \& \mathrm{pH}=4.25$
B
$\mathrm{K}_{\mathrm{eq}}=3.58 \times 10^{-11} \& \mathrm{pH}=4.19$
C
$\mathrm{K}_{\mathrm{eq}}=2.86 \times 10^{-11} \& \mathrm{pH}=3.23$
D
$\mathrm{K}_{\mathrm{eq}}=3.92 \times 10^{-10} \& \mathrm{pH}=4.07$
2
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
An Alkene " X " on reaction with hot acidified $\mathrm{KMnO}_4$ gave a mixture of Ethanoic acid and Propanone. Identify " X ".
A
Pent-2-ene
B
2-Methylbut-2-ene.
C
But-2-ene
D
2,3 -Dimethylbut-2-ene
3
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
Imagine an R - moiety of a pentapeptide molecule having one $-\mathrm{SH},-\mathrm{CONH}_2,-\mathrm{NH}_2$ groups each and two $-$COOH groups in the amino acids forming the pentapeptide. If the pH is maintained at 13.2, what would be the total number of negative charges on the pentapeptide?
A
4
B
2
C
3
D
5
4
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
An aqueous solution which contains $42 \%$ by weight $(\mathrm{w} / \mathrm{W})$ of a volatile liquid "A" of molar mass of $140 \mathrm{~g} / \mathrm{mol}$, has a vapour pressure of 2141.4 mm of Hg at $37^{\circ} \mathrm{C}$. What is the vapour pressure of the pure liquid " A "? Vapour pressure of water at $37^{\circ} \mathrm{C}$ is 2019.1 mm .
A
3457.6 mm
B
293 mm
C
2356.4 mm
D
2519.2 mm
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