Electrochemistry Test

Question 1
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Standard electrode potential data are useful for understanding the suitability of an oxidant in a redox titration. Some half-cell reactions and their standard potentials are given below:

$$MnO_{4}^{-}(aq)+8H^{+}(aq)+5e^{-}\rightarrow Mn^{2+}(aq)+4H_{2}O(l);$$ $$E^{\circ}= 1.51V$$
$$Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)+6e^{-}\rightarrow 2Cr^{3+}(aq)+7H_{2}O(l);$$ $$E^{\circ}= 1.38V$$
$$Fe^{3+}(aq)+e^{-}\rightarrow Fe^{2+}(aq);$$ $$E^{\circ}= 0.77V$$
$$Cl_{2}(g)+2e^{-}\rightarrow 2Cl^{-}(aq);$$ $$E^{\circ}= 1.40V$$

Identify the only incorrect statement regarding the quantitative estimation of aqueous $$Fe(NO_{3})_{2}$$

A
$$MnO_{4}^{-}$$ can be used in aqueous $$HCl$$

B
$$Cr_{2}O_{7}^{2-}$$ can be used in aqueous $$HCl$$

C
$$MnO_{4}^{-}$$ can be used in aqueous $$H_{2}SO_{4}$$

D
$$Cr_{2}O_{7}^{2-}$$ can be used in aqueous $$H_{2}SO_{4}$$

Question 2
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The decreasing order of standard electrode potential of $$Mg, K, Ba$$ and $$Ca$$ is

A
$$K,Ca,Ba,Mg$$

B
$$Ba, Ca, K, Mg$$

C
$$Ca, Mg, K, Ba$$

D
$$Mg, Ca, Ba, K$$

Question 3
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Two electrochemical cells are assembled in which the following reactions occur:

$$ V^{2+}+VO^{2+}+2H^{+} \rightarrow 2V^{3+}+H_{2}O\ ;\ E_{cell}^{\circ} = 0.616\ V$$

$$ V^{3+}+Ag^{+}+H_{2}O \rightarrow VO^{2+}+Ag(s)+2H^{+}\ ;\ E_{cell}^{\circ} = 0.439\ V$$

If $$ E_{Ag^{+}|Ag}^{\circ} = 0.799\ V,$$ what is $$ E_{V^{3+}|V^{2+}}^{\circ}?$$

A
$$-0.256\ V$$

B
$$+0.256\ V$$

C
$$+1.854\ V$$

D
$$-1.854\ V$$

Question 4
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From the following $$E^{\circ}$$ values for the half-cells:

$$(i)\ D\rightarrow D^{2+}+2e^{-};E^{\circ}=-1.5V$$

$$(ii)\ B^{+}+e^{-}\rightarrow B;E^{\circ}=-0.5V$$

$$(iii)\ A^{3-}\rightarrow A^{2-}+e^{-};E^{\circ}=1.5V$$

$$(iv)\ C^{2+}+e^{-}\rightarrow C^{+};E^{\circ}= +0.5V$$

Which combination of two half-cells would result in a cell with the largest potential?

A
$$(i)$$ and $$(iii)$$

B
$$(i)$$ and $$(iv)$$

C
$$(iii)$$ and $$(iv)$$

D
$$(ii)$$ and $$(iv)$$

Question 5
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Statement $$I$$: Electrolysis of $$ CuCl_{2}(aq)$$ gives 1 mole of Cu and 1 mole of $$ Cl_{2}$$ by the passage of suitable charge.
Statement $$II$$: Equal equivalents of Cu and $$ Cl_{2}$$ are formed during the passage of same charge.

A
If both statements are CORRECT, and Statement $$II$$ is the CORRECT explanation of Statement $$I$$.

B
If both statements are CORRECT, and Statement $$II$$ is NOT the CORRECT explanation of Statement $$I$$.

C
If Statement $$I$$ is CORRECT, but Statement $$II$$ is INCORRECT.

D
If Statement $$I$$ is INCORRECT,but Statement $$II$$ is CORRECT.

Question 6
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Statement $$I$$: An electrochemical cell can be set up only when the redox reaction is spontaneous.
Statement $$II$$: A reaction is spontaneous if free energy change at constant temperature and pressure is negative.

A
If both statements are Correct, and Statement $$II$$ is the Correct explanation of Statement $$I$$.

B
If both statements are Correct, and Statement $$II$$ is NOT the Correct explanation of Statement $$I$$.

C
If Statement $$I$$ is Correct, but Statement $$II$$ is Incorrect.

D
If Statement $$I$$ is Incorrect, but Statement $$II$$ is Correct.

Question 7
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The graph represent a current-voltage behaviour of water. Choose the correct option:

A
Ohm's law is obeyed

B
Electrolysis in general do not obey ohm's law

C
Dissociation takes place at E, and it obeys Ohm's law thereafter

D
Ohm's law is not valid for low voltage

Question 8
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Which of the following solutions have highest resistance?

A
1N - NaCl

B
0.05 N - NaCl

C
2N - NaCl

D
0.1 N - NaCl

Question 9
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Which of the following statements does not differentiate between electrochemical cell and electrolytic cell?

A
Spontaneous or non-spontaneous nature of the chemical process.

B
Chemical reactions occurring at the electrodes

C
Positive and negative nature of anode.

D
EMF measurement.

Question 10
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Statement $$II$$: In an electrochemical cell, anode and cathode are, respectively, negative and positive electrode.
Statement $$II$$: At anode, oxidation takes place and at cathode reduction takes place.

A
If both statements are CORRECT, and Statement $$II$$ is the CORRECT explanation of Statement $$I$$.

B
If both statements are CORRECT, and Statement $$II$$ is NOT the CORRECT explanation of Statement $$I$$.

C
If Statement $$I$$ is CORRECT, but Statement $$II$$ is INCORRECT.

D
If Statement $$I$$ is INCORRECT, but Statement $$II$$ is CORRECT.

Submit Test

Electrochemistr...

Question 1

$$MnO_{4}^{-}$$ can be used in aqueous $$HCl$$

$$Cr_{2}O_{7}^{2-}$$ can be used in aqueous $$HCl$$

$$MnO_{4}^{-}$$ can be used in aqueous $$H_{2}SO_{4}$$

$$Cr_{2}O_{7}^{2-}$$ can be used in aqueous $$H_{2}SO_{4}$$

Question 2

$$K,Ca,Ba,Mg$$

$$Ba, Ca, K, Mg$$

$$Ca, Mg, K, Ba$$

$$Mg, Ca, Ba, K$$

Question 3

$$-0.256\ V$$

$$+0.256\ V$$

$$+1.854\ V$$

$$-1.854\ V$$

Question 4

$$(i)$$ and $$(iii)$$

$$(i)$$ and $$(iv)$$

$$(iii)$$ and $$(iv)$$

$$(ii)$$ and $$(iv)$$

Question 5

If both statements are CORRECT, and Statement $$II$$ is the CORRECT explanation of Statement $$I$$.

If both statements are CORRECT, and Statement $$II$$ is NOT the CORRECT explanation of Statement $$I$$.

If Statement $$I$$ is CORRECT, but Statement $$II$$ is INCORRECT.

If Statement $$I$$ is INCORRECT,but Statement $$II$$ is CORRECT.

Question 6

If both statements are Correct, and Statement $$II$$ is the Correct explanation of Statement $$I$$.

If both statements are Correct, and Statement $$II$$ is NOT the Correct explanation of Statement $$I$$.

If Statement $$I$$ is Correct, but Statement $$II$$ is Incorrect.

If Statement $$I$$ is Incorrect, but Statement $$II$$ is Correct.

Question 7

Ohm's law is obeyed

Electrolysis in general do not obey ohm's law

Dissociation takes place at E, and it obeys Ohm's law thereafter

Ohm's law is not valid for low voltage

Question 8

1N - NaCl

0.05 N - NaCl

2N - NaCl

0.1 N - NaCl

Question 9

Spontaneous or non-spontaneous nature of the chemical process.

Chemical reactions occurring at the electrodes

Positive and negative nature of anode.

EMF measurement.

Question 10

If both statements are CORRECT, and Statement $$II$$ is the CORRECT explanation of Statement $$I$$.

If both statements are CORRECT, and Statement $$II$$ is NOT the CORRECT explanation of Statement $$I$$.

If Statement $$I$$ is CORRECT, but Statement $$II$$ is INCORRECT.

If Statement $$I$$ is INCORRECT, but Statement $$II$$ is CORRECT.

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