An oxidation-reduction reaction in which 3 electrons are transferred has a G° of 17.37 kJ mol–1 at 25°C. The value of Ecello(in V) is A× 10–2. The value of A is-
(1 F = 96,500 C mol–1)
1. -6
2. 4
3. -8
4. 2

Subtopic:  Relation between Emf, G, Kc & pH |
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The variation of molar conductivity with the concentration of an electrolyte (X) in an aqueous solution is shown in the given figure.

The electrolyte X is:

1. CH3COOH 2. KNO3
3. HCl 4. NaCl
Subtopic:   Kohlrausch Law & Cell Constant |
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For the given cell :

CusCu2+C1MCu2+C2MCus change in Gibbs energy G is negative, if:

1. C1=2C2

2. C2=C12

3. C1=C2

4. C2=2C1

Subtopic:  Nernst Equation |
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Compound A used as a strong oxidizing agent is amphoteric in nature. It is part of lead storage batteries. Compound A is :

1. PbO2

2. PbO

3. PbSO4

4. Pb3O4

Subtopic:  Batteries & Salt Bridge |
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If the Emf of the following cell Zn|Zn2+ (0.1 M) || Ag+ (0.01 M) | Ag at 298 K in V is \(x × 10^{–2}\). Find the value of x is:
(Rounded off to the nearest integer)

\(\begin{aligned} & \text {Given:} ~\mathrm{E}_{{\mathrm{Zn}^{2+}}/ \mathrm{Zn}}=-0.76 \mathrm{~V} \\ & \mathrm{E}_{\mathrm{Ag}^{+} / \mathrm{Ag}}^{\mathrm{o}}=+0.80 \mathrm{~V} ; \frac{2.303 \mathrm{RT}}{\mathrm{F}}=0.059 \end{aligned}\)

1. 157
2. 147
3. 144
4. 154

Subtopic:  Nernst Equation |
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Given below are the half-cell reactions :

Mn2++2eMn;E=1.18V2(Mn3++eMn2+);E=+1.51V

The Eº for 3Mn2+ → Mn + 2Mn3+ will be :

1. – 2.69 V; the reaction will occur

2. – 0.33 V; the reaction will not occur

3. – 0.33 V; the reaction will occur

4. – 2.69 V; the reaction will not occur

Subtopic:  Electrode & Electrode Potential |
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The reduction potential of hydrogen half-cell will be negative if:

1. P(H2) = 1atm and [H+] = 2.0 M

2. P(H2) = 1 atm and [H+] = 1.0 M

3. P(H2) = 2 atm and [H+] = 1.0 M

4. P(H2) = 2 atm and [H+] = 2.0 M

Subtopic:  Nernst Equation | Relation between Emf, G, Kc & pH |
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Resistance of 0.2 M solution of an electrolyte is 50 Ω. The specific conductance of the solution is 1.3 S m-1. If the resistance of the 0.4 M solution of the same electrolyte is \(260 \Omega,\) its molar conductivity is:
1. 6.25×104Sm2mol1
2. 625×104Sm2mol1
3. 62.5Sm2mol1
4. 6250Sm2mol1

Subtopic:  Conductance & Conductivity |
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The gibbs energy change (in J) for the given reaction at  [Cu2+] = [Sn2+] = 1 M and 298K is-

Cu(s)+Sn2+(aq.)Cu2+(aq.)+Sn(s)
Esn2+|Sn0=-0.16V,ECu2+|Cu0=0.34V,
TakeF=96500Cmol-1

1. 97850 J

2. 3500 J

3. 45660 J

4. 96500 J

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Consider the values of reduction potential:
\(\mathrm{Co}^{3+}+e^{-} \rightarrow \mathrm{Co}^{2+} ; E^{\circ}=+1.81 \mathrm{~V}\)
\(\mathrm{~Pb}^{4+}+2 e^{-} \rightarrow \mathrm{Pb}^{2+} ; E^{\circ}=+1.67 \mathrm{~V}\)
\(\mathrm{Ce}^{4+}+e^{-} \rightarrow C e^{3+} ; E^{\circ}=+1.61 \mathrm{~V}\)
\( \mathrm{Bi}^{3+}+3 e^{-} \rightarrow \mathrm{Bi} ; E^{\circ}=+0.20 \mathrm{~V}\)

The oxidizing power of the species will increase in the order of:

1.  \(C o^{3+}<C e^{4+}<B i^{3+}<P b^{4+}\)
2. \(\mathrm{Co}^{3+}<P b^{4+}<C e^{4+}<B i^{3+}\)
3. \(C e^{4+}<P b^{4+}<B i^{3+}<C o^{3+}\)
4. \(B i^{3+}<C e^{4+}<P b^{4+}<C o^{3+}\)
Subtopic:  Electrochemical Series |
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