1
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

$$ \begin{aligned} &\text { Using the data given below, the strongest reducing agent is: }\\ &\begin{array}{ll} \mathrm{E}_{\mathrm{Cr}_2 \mathrm{O}_7}^{\mathrm{o}}{ }^{2-} / \mathrm{Cr}^{3+}=1.33 \mathrm{~V} & \mathrm{E}_{\mathrm{MnO}_4^{-} / \mathrm{Mn}^{2+}}^{\mathrm{o}}=1.51 \mathrm{~V} \\ \mathrm{E}_{\mathrm{Cl}_2 / \mathrm{Cl}^{-}}^{\mathrm{O}}=1.36 \mathrm{~V} & \mathrm{E}_{\mathrm{Cr}^{3+} / \mathrm{Cr}}^{\mathrm{O}}=-0.74 \mathrm{~V} \end{array} \end{aligned} $$

A

$ Cr$

B

$\mathrm{Mn}^{2+}$

C

$\mathrm{Cr}^{3+}$

D

$\mathrm{Cl}^{-}$

2
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Consider a Galvanic cell in which the following reactions occurs: $\mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{Ag}^{+}(\mathrm{aq}) \rightarrow \mathrm{Fe}^{3+}(\mathrm{aq})+\mathrm{Ag}(\mathrm{s})$. What is the standard potential of the cell? Given: $\mathrm{E}^0\left(\mathrm{Ag}^{+} / \mathrm{Ag}\right)=\mathrm{aV} \quad \mathrm{E}^0\left(\mathrm{Fe}^{2+} / \mathrm{Fe}\right)=\mathrm{bV} \quad \& \quad \mathrm{E}^0\left(\mathrm{Fe}^{3+} / \mathrm{Fe}\right)=\mathrm{cV}$

A

$(a+2 b-3 c) V$

B

$(a+b+2 c) V$

C

$(a-2 c+b) V$

D

$(a+c-2 b) V$

3
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Identify the correct mathematical expression which represents the variation in molar conductivity of a weak acid having concentration C and ionisation constant $\mathrm{K}_{\mathrm{a}}$

( $\lambda_m^{\infty}=$ molar conductivity at infinite dilution, $\lambda_{\mathrm{m}}=$ molar conductivity at concentration C )

A

$K_a=\lambda_m^2 C / \lambda_m^{\infty}\left(\lambda_m^{\infty}-\lambda_m\right)$

B

$K_a=\lambda_m \lambda_m^{\infty}-\left(\lambda_m^{\infty}\right)^2+\lambda_m^2 C$

C

$\lambda_m+\lambda_m^{\infty}+K_a C^{\frac{1}{2}}=0$

D

$K_a=\lambda_m^2 C / \lambda_m^{\infty}\left(\lambda_m^{\infty}+\lambda_m\right)$

4
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

What will be the change in the electrode potential of chromium electrode dipping into chromic sulphate solution, when the electrolyte is diluted 10 times at $25^{\circ} \mathrm{C}$ ? $\left[\mathrm{E}^0\left(\mathrm{Cr}^{3+} / \mathrm{Cr}\right)\right]=-0.74 \mathrm{~V}$

A

Increase by 32.8 mV

B

Decrease by 19.7 mV

C

Decrease by 29.6 mV

D

Increase by 16.2 mV

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