COMEDK 2025 Morning Shift | Electrochemistry Question 9 | Chemistry

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

increasing the concentration of $\mathrm{Al}^{3+}$ and $\mathrm{Fe}^{2+}$

increasing the concentration of $\mathrm{Al}^{3+}$

increasing the concentration of $\mathrm{Fe}^{2+}$

decreasing the concentration of $\mathrm{Al}^{3+}$ and $\mathrm{Fe}^{2+}$

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

-0

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

The reaction occurring at the cathodic area is:

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

The reaction occurring at the cathodic area is:

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

Reaction occurring at anodic area is:

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

The overall reaction occurring during the corrosion process is:

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

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

-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.

Assertion is correct but Reason is incorrect statement.

Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.

Both Assertion and Reason are incorrect statements.

Assertion is incorrect but Reason is correct statement.

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

-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?

6.0

10.5

21.0

3.0

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