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The potential for the given half cell at $298 K$ is $(-)$ ............ $\times 10^{- 2} V .$

$2 H_{(aq)}^{+} + 2 e^{-} \to H_{2} (g)$

$[H^{+}] = 1 M, P_{H_{2}} = 2 atm$

(Given $2.303 RT / F = 0.06 V, \log 2 = 0.3$ )

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Important Questions on Electrochemistry

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

For the electrochemical cell,

Mg(s) |{Mg}^{2+} (aq,1 M)| |{Cu}^{2+} (aq,1 M)| Cu (s)

the standard emf of the cell is

2 .70 V

300 K .

When the concentration of

{Mg}^{2+}

is changed to

x M,

the cell potential changes to

2 .67 V

300 K .

The value of

x

is ________.

(given,

\frac{F}{R} {=11500 K V}^{- 1},

where

F

is the Faraday constant and

R

is the gas constants,

ln (10) = 2 .30

)

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

For the following electrochemical cell at

289 K,

Pt (s) | H_{2} (g, 1 bar) | H^{+} (aq, 1 M) | | M^{4 +} (aq .) {, M}^{2+} (aq .) | Pt (s)

E_{c e l l} = 0.092 V

when

\frac{[M^{2 +} (a q .)]}{[M^{4 +} (a q .)]} = 10^{x}

Given:

E_{M^{4 +} / M^{2 +}}^{0} = 0.151 V; 2.303 \frac{R T}{F} = 0.059

The value of

x

is -

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

To find the standard potential of

M^{3 +} / M

electrode, the following cell is constituted:

Pt / M / M^{3 +} (0 .001 mol L^{- 1}) / {Ag}^{+} (0 .01 mol L^{- 1}) / Ag

The emf of the cell is found to be

0.421 volt

298 K

. The standard potential of half-reaction

M^{3 +} + 3 e^{-} \to M

298 K

will be:

(Given:

E_{\frac{{Ag}^{+}}{Ag}}^{⊝}

298 K = 0.80 volt

)

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

In the cell,

Pt (s) |H_{2} (g, 1 bar)| HCl (aq) |AgCl (s)| Ag (s) |Pt (s),

the cell potential is

0 .92 V

when a

10^{- 6}

molar

HCl

solution is used. The standard electrode potential of

Ag | AgCl | {Cl}^{-}

electrode is:

(Given,

\frac{2 .303 RT}{F} = 0 .06 V

298 K

)

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

The pressure of

H_{2}

required to make the potential of hydrogen electrode zero in pure water at 298 K is:

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

The standard cell potential for

Zn |{Zn}^{2 +}| |{Cu}^{2 +}| Cu

is 1.10 V. When the cell is completely discharged,

\log [{Zn}^{2 +}] / [{Cu}^{2 +}]

is closest to

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

Which of the following ions does not liberate hydrogen gas on reaction with dilute acids?

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

What would be the electrode potential for the given half-cell reaction at

p H = 5 ?

2 H_{2} O \to O_{2} + 4 \overset{\oplus}{H} + 4 e^{-}; E_{r e d}^{0} = 1.23 V

(R = 8 .314 J {mol}^{- 1} K^{- 1}; Temp = 298 K; oxygen under standard atm . pressure of 1 bar)

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

Among the following metals, the strongest reducing agent is

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

The standard reduction potentials (in V) of a few metal ion/metal electrodes are given below.

{Cr}^{3 +} / Cr = - 0 .74; {Cu}^{2 +} / Cu = + 0 .34; {Pb}^{2 +} / Pb = - 0 .13; {Ag}^{+} / Ag = + 0 .8 .

The reducing strength of the metals follows the order

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

Given

E_{{Cr}^{3 +} / Cr}^{o} = - 0.74 {V;  E}_{{MnO}_{4}^{-} / {Mn}^{2 +}}^{o} = 1.51 V

E_{{Cr}_{2} O_{7}^{2 -} / {Cr}^{3 +}}^{o} = 1.33 {V;   E}_{{Cl}_{2} | {Cl}^{-}}^{o} = 1.36 V

Based on the data given above, strongest oxidising agent will be:

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

The standard electrode potentials

(E_{M^{+} / M}^{o})

of four metals

A, B, C

and

D

are

- 1 .2 V,

0 .6 V

0 .85 V

and

- 0 .76 V

, respectively. The sequence of deposition of metals on applying potential is

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

In the electrochemical cell:

Zn |{ZnSO}_{4} (0 .01 M)| |{CuSO}_{4} (1 .0 M)| Cu,

the emf of this Daniel cell is

E_{1}

. When the concentration

{ZnSO}_{4}

is changed to

1 .0 M

and that of

{CuSO}_{4}

changed to

0 .01 M,

the emf changes to

E_{2}

. From the following, which one is the relationship between

E_{1}

and

E_{2}

? (Given,

\frac{RT}{F} = 0 .059

)

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

The metal that cannot be obtained by the electrolysis of an aqueous solution of its salt is

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

Given that,

$E_{O_{2} / H_{2} O}^{o} = + 1 .23 V;$
$E_{S_{2} O_{8}^{2 -} / {SO}_{4}^{2 -}}^{o} = 2 .05 V$
$E_{{Br}_{2} / {Br}^{-}}^{o} = + 1.09 V;$
$E_{{Au}^{3 +} / Au}^{o} = 1 .4 V$

The strongest oxidizing agent is

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

For an electrochemical cell

Sn (s) |{Sn}^{2 +} (aq, 1 M)| |{Pb}^{2 +} (aq, 1 M)| Pb (s)

the ratio

\frac{[{Sn}^{2 +}]}{[{Pb}^{2 +}]}

when this cell attains equilibrium is _______.
(Given:

E_{{Sn}^{2 +}| Sn}^{0} = - 0 .14 V, E_{{Pb}^{2 +}| Pb}^{0} = - 0 .13 V, \frac{2 .303 RT}{F} = 0 .06 \log 2.15 = \frac{1}{3}

)

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

The voltage of the cell consisting of

Li (s)

and

F_{2} (g)

electrodes is

5.92 V

at standard condition at

298 K

. What is the voltage if the electrolyte consists of

2 M LiF

.
Given that,

\ln 2 = 0 .693, R = 8 .314 {JK}^{- 1} {mol}^{- 1} F = 96500 C {mol}^{- 1}

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

298 K

, the standard reduction potentials are

1.51 V

for

{M n O}_{4}^{-} | M n^{2 +}

1.36 V

for

C l_{2} | C l^{-}

1.07 V

for

B r_{2} | B r^{-}

0.54 V

for

I_{2} | I^{-}

. At

pH = 3

, permanganate is expected to oxidize:

(\frac{R T}{F} = 0.059)

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrode Potentials and Cell Potential

Consider the following reduction processes:

{Zn}^{2 +} + 2 e^{-} \to Zn (s); E^{o} = - 0 .76 V

{Ca}^{2 +} + 2 e^{-} \to Ca (s); E^{o} = - 2 .87 V

{Mg}^{2 +} + 2 e^{-} \to Mg (s); E^{o} = - 2 .36 V

{Ni}^{2 +} + 2 e^{-} \to Ni (s); E^{o} = - 0 .25 V

The reducing power of the metals increases in the order:

The potential for the given half cell at 298K is -............ ×10-2V. 2H(aq)++2e-→H2( g) H+=1M,PH2=2 atm (Given2.303 RT/F=0.06 V, log2=0.3)

Important Questions on Electrochemistry

Learn and Prepare for any exam you want !

The potential for the given half cell at $298 K$ is $(-)$ ............ $\times 10^{- 2} V .$

$2 H_{(aq)}^{+} + 2 e^{-} \to H_{2} (g)$

$[H^{+}] = 1 M, P_{H_{2}} = 2 atm$

(Given $2.303 RT / F = 0.06 V, \log 2 = 0.3$ )