Electrochemistry · JEE Main previous year questions

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2019 11 questions

Q822019 · 12 Apr 2019 · Shift 1
Given $Co^{3 +} + e^{-} \to Co^{2 +}; E^{\circ} = + 1.81 V$ $Pb^{4 +} + 2 e^{-} \to Pb^{2 +}; E^{\circ} = + 1.67 V$ $Ce^{4 +} + e^{-} \to Ce^{3 +}; E^{\circ} = + 1.61 V$ $Bi^{3 +} + 3 e^{-} \to Bi; E^{\circ} = + 0.20 V$ Oxidizing power of the species will increase in the order :
1. A. $Co^{3 +} < Ce^{4 +} < Bi^{3 +} < Pb^{4 +}$
2. B. $Co^{3 +} < Pb^{4 +} < Ce^{4 +} < Bi^{3 +}$
3. C. $Ce^{4 +} < Pb^{4 +} < Bi^{3 +} < Co^{3 +}$
4. D. $Bi^{3 +} < Ce^{4 +} < Pb^{4 +} < Co^{3 +}$
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Answer: D
Q652019 · 12 Apr 2019 · Shift 2
The decreasing order of electrical conductivity of the following aqueous solutions is : 0.1 M Formic acid (A), 0.1 M Acetic acid (B), 0.1 M Benzoic acid (C)
1. A.A > B > C
2. B.C > B > A
3. C.A > C > B
4. D.C > A > B
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Answer: C
Q662019 · 10 Apr 2019 · Shift 1
Consider the statements S1 and S2 S1 : Conductivity always increases with decrease in the concentration of electrolyte. S2 : Molar conductivity always increases with decrease in the concentration of electrolyte. The correct option among the following is :
1. A.Both S1 and S2 are wrong
2. B.S1 is correct and S2 is wrong
3. C.Both S1 and S2 are correct
4. D.S1 is wrong and S2 is correct
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Answer: D
Q802019 · 10 Apr 2019 · Shift 2
1. A.
2. B.
3. C.
4. D.
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Answer: A
Q742019 · 9 Apr 2019 · Shift 1
The standard Gibbs energy for the given cell reaction in $kJ mo l^{- 1}$ at 298 K is : $Zn (s) + C u^{2 +} (aq) \to Z n^{2 +} (aq) + Cu (s)$ , E° = 2 V at 298 K (Faraday's constant, $F = 96000 C mo l^{- 1}$ )
1. A.384
2. B.−192
3. C.−384
4. D.192
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Answer: C
Q702019 · 9 Apr 2019 · Shift 2
A solution of $Ni (N O_{3})_{2}$ is electrolysed between platinum electrodes using 0.1 Faraday electricity. How many moles of Ni will be deposited at the cathode?
1. A.0.10
2. B.0.15
3. C.0.20
4. D.0.05
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Answer: D
Q612019 · 8 Apr 2019 · Shift 2
Calculate the standard cell potential in (V) of the cell in which following reaction takes place : $F e^{2 +} (aq) + A g^{+} (aq) \to F e^{3 +} (aq) + Ag (s)$ Given that $E_{A g^{+} /Ag}^{o} = x V$ $E_{F e^{2 +} /Fe}^{o} = y V$ $E_{F e^{3 +} /Fe}^{o} = z V$
1. A.x + 2y − 3z
2. B.x − z
3. C.x − y
4. D.x + y − z
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Answer: A
Q762019 · 12 Jan 2019 · Shift 1
The standard electrode potential $E^{o}$ and its temperature coefficient $(\frac{d E ^{o}}{d T})$ for a cell are 2V and $- 5 \times 1 0^{- 4} V K^{- 1}$ at 300 K respectively. The cell reaction is $Zn (s) + C u^{2 +} (aq) ⟶ Z n^{2 +} (aq) + Cu (s)$ The standard reaction enthalpy $(Δ_{r} H^{o})$ at 300 K in $kJ mo l^{- 1}$ is, [Use $R = 8 J K^{- 1} mo l^{- 1}$ and $F = 96, 000C mo l^{- 1}$ ]
1. A. $- 412.8$
2. B. $- 384.0$
3. C. $192.0$
4. D. $206.4$
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Answer: A
Q902019 · 12 Jan 2019 · Shift 1
In the Hall-Heroult process, aluminium is formed at the cathode. The cathode is made out of -
1. A.Copper
2. B.Platinum
3. C.Carbon
4. D.Pure aluminium
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Answer: C
Q632019 · 12 Jan 2019 · Shift 2
$Λ_{m}^{\circ}$ for NaCl, HCl and NaA are 126.4, 425.9 and $100.5 S c m^{2} mo l^{- 1}$ , respectively. If the conductivity of 0.001 M HA is- $5 \times 1 0^{- 5} S c m^{- 1}$ , degree of dissociation of HA is -
1. A.0.50
2. B.0.125
3. C.0.25
4. D.0.75
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Answer: B
Q792019 · 9 Jan 2019 · Shift 1
The anodic half-cell of lead-acid battery is recharged using electricity of $0.05 Faraday$ . The amount of $PbS O_{4}$ electrolyzed in g during the process is : (Molar mass of $PbS O_{4} = 303 g mol^{- 1}$ )
1. A.22.8
2. B.15.2
3. C.7.6
4. D.11.4
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Answer: C