QBManager

ELECTROCHEMISTRY

276249 The standard emf of $Zn - Cu$ voltaic cell is

1

2.1 V

2

2.8 V

3

1.2 V

4

1.1 V

Explanation:

The standard electromotive force (EMF) of $Zn - Cu$ voltaic cell is $1.1 V$ at room temperature.
$E_{cell} = E_{cell} - \frac{0.059}{2} \log \frac{[{Zn}^{2 +}]}{[{Cu}^{2 +}]}$
$= 1.10 - \frac{0.059}{2} \log \frac{0.1}{0.1}$
$\begin{aligned} E_{cell} & = 1.10 - \frac{0.059}{2} \log 1 \\ = 1.10 - 0 \\ = 1.10 \end{aligned}$

SRMJEEE - 2015

ELECTROCHEMISTRY

276251 The cathode reaction in the dry cell will be

1

{Zn}_{(s)} ⟶ {Zn}^{2 +} + 2 e^{-}

2

{MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}

3

Zn (Hg) + 2 {OH}^{-} ⟶ {ZnO}_{(s)} + H_{2} O + 2 e

4

MnO (OH) + {NH}_{3} ⟶ {MnO}_{2} + {NH}_{4}^{+} + 2 e

Explanation:

The cathode reaction in the dry cell will be-
${MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}$

COMEDK 2015

ELECTROCHEMISTRY

276260 Which metal is protected from corrosion by a layer of its own oxide?

1

Tl

2

Ag

3

Al

4

Au

Explanation:

Aluminum reacts with air to form ${Al}_{2} O_{3}$ which protects the metal from further corrosion.
$Al$ is oxidized to form ${Al}_{2} O_{3}$ which forms a protective coating on the surface of the metal.

AMU-2013

ELECTROCHEMISTRY

276261 During charging of lead storage battery, the reaction occurring at the cathode is

1

{Pb}^{2 +} + 2 e^{-} ⟶ Pb

2

Pb ⟶ {Pb}^{2 +} + 2 e^{-}

3

{PbSO}_{4} + 2 H_{2} O ⟶ 2 {PbO}_{2} + 4 H^{+} + {SO}_{4}^{2 -} + 2 e^{-}

4

{Pb}^{2 +} + {SO}_{4}^{2 -} ⟶ {PbSO}_{4}

Explanation:

A lead storage battery is a secondary cell so we can charge the battery by passing our current directly so, it can be relies. At anode
$Pb + {SO}_{4}^{2 -} \to {PbSO}_{4} + 2 e^{-}$
At cathode
${PbO}_{2} + {SO}_{4}^{2 -} + 4 H^{+} + 2 e^{-} \to {PbSO}_{4} + 2 H_{2} O$

AMU-2012

ELECTROCHEMISTRY

276249 The standard emf of $Zn - Cu$ voltaic cell is

1

2.1 V

2

2.8 V

3

1.2 V

4

1.1 V

Explanation:

The standard electromotive force (EMF) of $Zn - Cu$ voltaic cell is $1.1 V$ at room temperature.
$E_{cell} = E_{cell} - \frac{0.059}{2} \log \frac{[{Zn}^{2 +}]}{[{Cu}^{2 +}]}$
$= 1.10 - \frac{0.059}{2} \log \frac{0.1}{0.1}$
$\begin{aligned} E_{cell} & = 1.10 - \frac{0.059}{2} \log 1 \\ = 1.10 - 0 \\ = 1.10 \end{aligned}$

SRMJEEE - 2015

ELECTROCHEMISTRY

276251 The cathode reaction in the dry cell will be

1

{Zn}_{(s)} ⟶ {Zn}^{2 +} + 2 e^{-}

2

{MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}

3

Zn (Hg) + 2 {OH}^{-} ⟶ {ZnO}_{(s)} + H_{2} O + 2 e

4

MnO (OH) + {NH}_{3} ⟶ {MnO}_{2} + {NH}_{4}^{+} + 2 e

Explanation:

The cathode reaction in the dry cell will be-
${MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}$

COMEDK 2015

ELECTROCHEMISTRY

276260 Which metal is protected from corrosion by a layer of its own oxide?

1

Tl

2

Ag

3

Al

4

Au

Explanation:

Aluminum reacts with air to form ${Al}_{2} O_{3}$ which protects the metal from further corrosion.
$Al$ is oxidized to form ${Al}_{2} O_{3}$ which forms a protective coating on the surface of the metal.

AMU-2013

ELECTROCHEMISTRY

276261 During charging of lead storage battery, the reaction occurring at the cathode is

1

{Pb}^{2 +} + 2 e^{-} ⟶ Pb

2

Pb ⟶ {Pb}^{2 +} + 2 e^{-}

3

{PbSO}_{4} + 2 H_{2} O ⟶ 2 {PbO}_{2} + 4 H^{+} + {SO}_{4}^{2 -} + 2 e^{-}

4

{Pb}^{2 +} + {SO}_{4}^{2 -} ⟶ {PbSO}_{4}

Explanation:

A lead storage battery is a secondary cell so we can charge the battery by passing our current directly so, it can be relies. At anode
$Pb + {SO}_{4}^{2 -} \to {PbSO}_{4} + 2 e^{-}$
At cathode
${PbO}_{2} + {SO}_{4}^{2 -} + 4 H^{+} + 2 e^{-} \to {PbSO}_{4} + 2 H_{2} O$

AMU-2012

ELECTROCHEMISTRY

276249 The standard emf of $Zn - Cu$ voltaic cell is

1

2.1 V

2

2.8 V

3

1.2 V

4

1.1 V

Explanation:

The standard electromotive force (EMF) of $Zn - Cu$ voltaic cell is $1.1 V$ at room temperature.
$E_{cell} = E_{cell} - \frac{0.059}{2} \log \frac{[{Zn}^{2 +}]}{[{Cu}^{2 +}]}$
$= 1.10 - \frac{0.059}{2} \log \frac{0.1}{0.1}$
$\begin{aligned} E_{cell} & = 1.10 - \frac{0.059}{2} \log 1 \\ = 1.10 - 0 \\ = 1.10 \end{aligned}$

SRMJEEE - 2015

ELECTROCHEMISTRY

276251 The cathode reaction in the dry cell will be

1

{Zn}_{(s)} ⟶ {Zn}^{2 +} + 2 e^{-}

2

{MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}

3

Zn (Hg) + 2 {OH}^{-} ⟶ {ZnO}_{(s)} + H_{2} O + 2 e

4

MnO (OH) + {NH}_{3} ⟶ {MnO}_{2} + {NH}_{4}^{+} + 2 e

Explanation:

The cathode reaction in the dry cell will be-
${MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}$

COMEDK 2015

ELECTROCHEMISTRY

276260 Which metal is protected from corrosion by a layer of its own oxide?

1

Tl

2

Ag

3

Al

4

Au

Explanation:

Aluminum reacts with air to form ${Al}_{2} O_{3}$ which protects the metal from further corrosion.
$Al$ is oxidized to form ${Al}_{2} O_{3}$ which forms a protective coating on the surface of the metal.

AMU-2013

ELECTROCHEMISTRY

276261 During charging of lead storage battery, the reaction occurring at the cathode is

1

{Pb}^{2 +} + 2 e^{-} ⟶ Pb

2

Pb ⟶ {Pb}^{2 +} + 2 e^{-}

3

{PbSO}_{4} + 2 H_{2} O ⟶ 2 {PbO}_{2} + 4 H^{+} + {SO}_{4}^{2 -} + 2 e^{-}

4

{Pb}^{2 +} + {SO}_{4}^{2 -} ⟶ {PbSO}_{4}

Explanation:

A lead storage battery is a secondary cell so we can charge the battery by passing our current directly so, it can be relies. At anode
$Pb + {SO}_{4}^{2 -} \to {PbSO}_{4} + 2 e^{-}$
At cathode
${PbO}_{2} + {SO}_{4}^{2 -} + 4 H^{+} + 2 e^{-} \to {PbSO}_{4} + 2 H_{2} O$

AMU-2012

ELECTROCHEMISTRY

276249 The standard emf of $Zn - Cu$ voltaic cell is

1

2.1 V

2

2.8 V

3

1.2 V

4

1.1 V

Explanation:

The standard electromotive force (EMF) of $Zn - Cu$ voltaic cell is $1.1 V$ at room temperature.
$E_{cell} = E_{cell} - \frac{0.059}{2} \log \frac{[{Zn}^{2 +}]}{[{Cu}^{2 +}]}$
$= 1.10 - \frac{0.059}{2} \log \frac{0.1}{0.1}$
$\begin{aligned} E_{cell} & = 1.10 - \frac{0.059}{2} \log 1 \\ = 1.10 - 0 \\ = 1.10 \end{aligned}$

SRMJEEE - 2015

ELECTROCHEMISTRY

276251 The cathode reaction in the dry cell will be

1

{Zn}_{(s)} ⟶ {Zn}^{2 +} + 2 e^{-}

2

{MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}

3

Zn (Hg) + 2 {OH}^{-} ⟶ {ZnO}_{(s)} + H_{2} O + 2 e

4

MnO (OH) + {NH}_{3} ⟶ {MnO}_{2} + {NH}_{4}^{+} + 2 e

Explanation:

The cathode reaction in the dry cell will be-
${MnO}_{2} + {NH}_{4}^{+} + e^{-} ⟶ MnO (OH) + {NH}_{3}$

COMEDK 2015

ELECTROCHEMISTRY

276260 Which metal is protected from corrosion by a layer of its own oxide?

1

Tl

2

Ag

3

Al

4

Au

Explanation:

Aluminum reacts with air to form ${Al}_{2} O_{3}$ which protects the metal from further corrosion.
$Al$ is oxidized to form ${Al}_{2} O_{3}$ which forms a protective coating on the surface of the metal.

AMU-2013

ELECTROCHEMISTRY

276261 During charging of lead storage battery, the reaction occurring at the cathode is

1

{Pb}^{2 +} + 2 e^{-} ⟶ Pb

2

Pb ⟶ {Pb}^{2 +} + 2 e^{-}

3

{PbSO}_{4} + 2 H_{2} O ⟶ 2 {PbO}_{2} + 4 H^{+} + {SO}_{4}^{2 -} + 2 e^{-}

4

{Pb}^{2 +} + {SO}_{4}^{2 -} ⟶ {PbSO}_{4}

Explanation:

A lead storage battery is a secondary cell so we can charge the battery by passing our current directly so, it can be relies. At anode
$Pb + {SO}_{4}^{2 -} \to {PbSO}_{4} + 2 e^{-}$
At cathode
${PbO}_{2} + {SO}_{4}^{2 -} + 4 H^{+} + 2 e^{-} \to {PbSO}_{4} + 2 H_{2} O$

AMU-2012

Explanation:

Explanation:

Explanation:

Explanation:

Question Bank Series

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation:

Explanation: