1
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0
For the cell reaction $4 \mathrm{Br}^{-}+\mathrm{O}_2+4 \mathrm{H}^{+} \rightarrow 2 \mathrm{Br}_2+2 \mathrm{H}_2 \mathrm{O}$ at 298 K , the $\mathrm{E}^0$ cell $=0.16 \mathrm{~V}$. What would be the $\mathrm{K}_{\mathrm{c}}$ (Equilibrium constant) value if the reverse reaction were to take place?
A
$2.012 \times 10^{-10}$
B
$8.47 \times 10^{-9}$
C
$1.422 \times 10^{-11}$
D
$7.031 \times 10^{-10}$
2
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Two statements, one Assertion and the other Reason, are given. Choose the correct option.

Assertion : During the electrolysis of aqueous $\mathrm{NaCl}, \mathrm{Cl}_2$ is liberated at the anode in preference to $\mathrm{O}_2$ and water gets reduced to $\mathrm{H}_2$ at cathode.

Reason : The reaction at Anode with lower oxidation potential is not preferred due to over potential of Oxygen.

A
Both Assertion and Reason are incorrect.
B
Both Assertion and Reason are correct.
C
Assertion is correct but Reason is incorrect.
D
Assertion is incorrect but Reason is correct.
3
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0
For a cell $2 \mathrm{M}_{(\mathrm{S})}+\mathrm{O}_2(\mathrm{~g})+4 \mathrm{H}^{+} \rightarrow 2 \mathrm{M}^{2+}(\mathrm{aq})+2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{l})}$ the $\mathrm{E}^0$ cell $=+1.67 \mathrm{~V}$. When $\left[\mathrm{M}^{2+}\right]$ is $1.0 \times 10^{-3} \mathrm{M}$ and $\mathrm{p}\left(\mathrm{O}_2\right)$ is 0.1 atm , the EMF of the cell becomes +1.57 V . Calculate the pH of the electrochemical cell.
A
3.49
B
2.95
C
5.24
D
12.01
4
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0

When $0.1 \mathrm{~mol} \mathrm{~L}^{-1}$ of KCl was filled in a Conductivity cell the resistance was 80 ohms at 298 K . (Conductivity of 0.1 M KCl at 298 K is $1.29 \mathrm{~S} \mathrm{~m}^{-1}$. The same cell when filled with an unknown electrolyte of concentration 0.025 M , had a resistance of 92 ohms. What is the Molar conductivity of the electrolyte at the given concentration?

A
$220.6 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$
B
$0.2206 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$
C
$448 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$
D
$0.449 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$
COMEDK Subjects
EXAM MAP