1
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
The EMF of the cell $\mathrm{Al} / \mathrm{Al}^{3+}(0.01 \mathrm{M}) \| \mathrm{Fe}^{2+}(0.02 \mathrm{M}) / \mathrm{Fe}$ is 1.209 V . The EMF of the cell can be increased by
A
increasing the concentration of $\mathrm{Al}^{3+}$ and $\mathrm{Fe}^{2+}$
B
increasing the concentration of $\mathrm{Al}^{3+}$
C
increasing the concentration of $\mathrm{Fe}^{2+}$
D
decreasing the concentration of $\mathrm{Al}^{3+}$ and $\mathrm{Fe}^{2+}$
2
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Identify the correct statement regarding corrosion of iron rod left exposed to atmosphere.

A

The reaction occurring at the cathodic area is:

$$ \mathrm{O}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{l})+4 \mathrm{e} \rightarrow 4 \mathrm{OH}^{-} $$

B

The reaction occurring at the cathodic area is:

$$ \mathrm{O}_2(\mathrm{~g})+4 \mathrm{H}^{+}(\mathrm{aq})+4 \mathrm{e} \rightarrow 2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) ; \mathrm{E}^0=+1.23 \mathrm{~V} $$

C

Reaction occurring at anodic area is:

$$ 2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{O}_2(\mathrm{~g})+4 \mathrm{H}^{+}+4 \mathrm{e} $$

D

The overall reaction occurring during the corrosion process is:

$$ 2 \mathrm{Fe}_{(\mathrm{S})}+3 / 2 \mathrm{O}_2(\mathrm{~g})+6 \mathrm{H}^{+} \rightarrow 2 \mathrm{Fe}^{3+}+3 \mathrm{H}_2 \mathrm{O} ; \mathrm{E}^0=-1.23 \mathrm{~V} $$

3
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Given below are 2 statements: Assertion and Reason. Choose the correct option.

Assertion: When Molar conductivity for a strong electrolyte is plotted versus $$\sqrt{C}(\mathrm{~mol} / \mathrm{L})^{1 / 2}$$, a straight line is obtained with intercept equal to Molar conductivity at infinite dilution for the electrolyte and Slope equal to $$-\mathrm{A}$$. All electrolytes of a given type have the same $$\mathrm{A}$$ value.

Reason: At infinite dilution, strong electrolytes of the same type will have different number of ions due to incomplete dissociation.

A
Assertion is correct but Reason is incorrect statement.
B
Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
C
Both Assertion and Reason are incorrect statements.
D
Assertion is incorrect but Reason is correct statement.
4
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

What is the quantity of charge, in Faraday units, required for the reduction of 3.5 moles of $$\mathrm{Cr}_2 \mathrm{O} 7^{2-}$$ in acid medium?

A
6.0
B
10.5
C
21.0
D
3.0
COMEDK Subjects
EXAM MAP