Electrochemistry

The standard electrode potential ( $\mathrm{E}^{\circ}$ ) for the half-cell reaction $\mathrm{Fe}^{3+}+\mathrm{e}^{-} \rightarrow \mathrm{Fe}^{2+}$ at 298 K is (Given : $\mathrm{E}^{\circ}\left(\mathrm{Fe}^{3+} / \mathrm{Fe}\right)=-0.04 \m...

For a salt XY, which is a strong electrolyte, the plot of $\Lambda_{\mathrm{m}}$ versus $\sqrt{\mathrm{c}}$ has a slope of $-90.0 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-3 / 2} \mathrm{L}^{1 / 2}$ at 298 K . At 0.01 M concentration of $\...

Calculate emf of the half cell given below :
$$ \begin{aligned} & \mathrm{Pt}(\mathrm{~s})\left|\mathrm{H}_2(\mathrm{~g}, 2 \mathrm{~atm})\right| \mathrm{HCl}(\mathrm{aq}, 0.02 \mathrm{M}) \\ & \mathrm{E}_{\mathrm{H}_2 / \mathrm{H}^{+}}^{\c...

A solution of copper sulphate is electrolysed for 10 minutes with a current of 1.5 amperes. The mass of copper deposited at cathode is :
(Given : Molar mass of $\mathrm{Cu}=63 \mathrm{~g} \mathrm{~mol}^{-1}$;
$$ \left.1 \mathrm{~F}=96487 \m...

The standard cell potential of the following cell \(\mathrm{Zn}\left|\mathrm{Zn}^{2+}(\mathrm{aq})\right| \mathrm{Fe}^{2+}(\mathrm{aq}) \mid \mathrm{Fe}\) is \(0.32 \mathrm{~V}\). Calculate the standard Gibbs energy change for the reaction:...

From the following select the one which is not an example of corrosion.

Mass in grams of copper deposited by passing 9.6487 A current through a voltmeter containing copper sulphate solution for 100 seconds is (Given : Molar mass of $$\mathrm{Cu}: 63 \mathrm{~g} \mathrm{~mol}^{-1}, 1 \mathrm{~F}=96487 \mathrm{C}...

Match List I with List II.

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The correct value of cell potential in volt for the reaction that occurs when the following two half cells are connected, is
$$\begin{aligned}
& \mathrm{Fe}_{(\mathrm{aq})}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Fe}(\mathrm{s}), \mathrm{...

Molar conductance of an electrolyte increase with dilution according to the equation:
\(\Lambda_{\mathrm{m}}=\Lambda_{\mathrm{m}}^{\circ}-\mathrm{A} \sqrt{\mathrm{c}}\)
Which of the following statements are true?
(A) This equation applies t...

The \(\mathrm{E}^{\Theta}\) values for
$$\begin{aligned}
& \mathrm{Al}^{+} / \mathrm{Al}=+0.55 \mathrm{~V} \text { and } \mathrm{Tl}^{+} / \mathrm{Tl}=-0.34 \mathrm{~V} \\
& \mathrm{Al}^{3+} / \mathrm{Al}=-1.66 \mathrm{~V} \text { and } \ma...

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A : In equation \(\mathrm{\Delta_rG=-nFE_{cell}}\), value of \(\mathrm{\Delta_rG}\) depends on n.
Reason R : $$\mathrm{E_{cell}}...

The conductivity of centimolar solution of \(\mathrm{KCl}\) at \(25^{\circ} \mathrm{C}\) is \(0.0210 ~\mathrm{ohm}^{-1} \mathrm{~cm}^{-1}\) and the resistance of the cell containing the solution at \(25^{\circ} \mathrm{C}\) is $$60 ~\mathrm...

Standard electrode potential for the cell with cell reaction
Zn(s) + Cu2+(aq) \(\to\) Zn2+(aq) + Cu(s)
is 1.1 V. Calculate the standard Gibbs energy change for the cell reaction. (Given F = 96487 C mol\(-\)1)

Two half cell reactions are given below.
\(C{o^{3 + }} + {e^ - } \to C{o^{2 + }},\,\,\,\,\,\,\,\,\,E_{C{o^{2 + }}/C{o^{3 + }}}^0 = - 1.81\,V\)
\(2A{l^{3 + }} + 6{e^ - } \to 2Al(s),\,\,\,E_{Al/A{l^{3 + }}}^0 = + 1.66\,V\)
The standard EMF ...

Find the emf of the cell in which the following reaction takes place at 298 K
Ni(s) + 2Ag+ (0.001 M) \(\to\) Ni2+ (0.001 M) + 2Ag(s)
(Given that E\(_{cell}^o\) = 10.5 V, \({{2.303\,RT} \over F} = 0.059\) at 298 K)

Given below are half cell reactions:
\(MnO_4^ - + 8{H^ + } + 5{e^ - } \to M{n^{2 + }} + 4{H_2}O\),
\(E_{M{n^{2 + }}/MnO_4^ - }^o = - 1.510\,V\)
\({1 \over 2}{O_2} + 2{H^ + } + 2{e^ - } \to {H_2}O\)
\(E_{{O_2}/{H_2}O}^o = + 1.223\,V\)
Wil...

At 298 K, the standard electrode potentials of Cu2+ / Cu, Zn2+ / Zn, Fe2+ / Fe and Ag+ / Ag are 0.34 V, \(-\)0.76 V, \(-\)0.44 V V and 0.80 V, respectively.
On the basis of standard electrode potential, predict which of the following reacti...

The molar conductivity of 0.007 M acetic acid is 20 S cm2 mol\(-\)1. What is the dissociation constant of acetic acid? Choose the correct option.[\(\Lambda _{{H^ + }}^o\) = 350 S cm2 mol\(-\)1\(\Lambda _{C{H_3}CO{O^ - }}^o\) = 50 S cm2 mol$...

The molar conductance of NaCl, HCl and CH3COONa at infinite dilution are 126.45, 426.16 and 91.0 S cm2 mol\(-\)1 respectively. The molar conductance of CH3COOH at infinite dilution is. Choose the right option for your answer.

On electrolysis of dil. sulphuric acid using Platinum (Pt) electrode, the product obtained at anode will be :

The number of Faradays(F) required to produce 20 g of calcium from molten CaCl2 (Atomic mass of Ca = 40 g mol-1) is :

For the cell reaction
2Fe3+(aq) + 2I–
(aq) \(\to\) 2Fe2+(aq) + I2(aq)
\({E_{cell}^\Theta }\) = 0.24 V at 298 K. The standard Gibbs energy (\(\Delta\)rGo) of the cell reaction is :
[Given that Faraday constant F = 96500 C mol–1]

For a cell involving one electron \(E_{cell}^\Theta\) = 0.59 V at 298 K, the equilibrium constant for the cell reaction is :
[Given that \({{2.303RT} \over F}\) = 0.059 V at T = 298 K ]

Consider the change in oxidation state of
bromine corresponding to different emf values
as shown in the given diagram :

Then the species undergoing disproportionation
is :

In the electrochemical cell :
\(Zn\left| {ZnS{O_4}\left( {0.01\,M} \right)} \right|\)\(\left| {CuS{O_4}\left( {1.0M} \right)} \right|Cu,\)
the emf of this Daniell cell is E1. When the concentration of ZnSO4 is changed to 1.0 M and that of C...

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

The number of electrons delivered at the cathode during electrolysis by a current of 1 ampere in 60 seconds is (charge on electron = 1.60 \(\times\) 10\(-\)19C)

The molar conductivity of a 0.5 mol/dm3 solution of AgNO3 with electrolytic conductivity of 5.76 \(\times\) 10\(-\)3 S cm\(-\)1 at 298 K is

During the electrolysis of molten sodium chloride, the time required to produce 0.10 mol of chlorine gas using a current of 3 amperes is

If the Eocell for a given reaction has a negative value, which of the following gives the correct relationships for the values of \(\Delta\)Go and Keq ?

The pressure of H2 required to make the potential of H2-electrode zero in pure water at 298 K is

A device that converts energy of combustion of fuels like hydrogen and methane, directly into electrical energy is known as

Aqueous solution of which of the following compounds is the best conductor of electric current ?

The weight of silver (at. wt. = 108) displaced by a quantity of electricity which displaces 5600 mL of O2 at STP will be

When 0.1 mol MnO\(_4^{2 - }\) is oxidised the quantity of electricity required to completely oxidise MnO\(_4^{2 - }\) to MnO\(_4^ -\) is

How many gram of cobalt metal will be deposited when a solution of cobalt (II) chloride is electrolyzed with a current of 10 amperes for 109 minutes (1 Faraday = 96,500 C; Atomic mass of Co = 59 u)

Consider the half-cell reduction reaction
Mn2+ + 2e\(-\) \(\to\) Mn, Eo = \(-\)1.18 V
Mn2+ \(\to\) Mn3+ + e\(-\), Eo = \(-\) 1.51 V
The \(E\)o for the reaction 3 Mn2+ \(\to\) Mno + 2Mn3+, and possibility of the forward reaction are ...

A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of electrode would be

A button cell used in watches function as following.
Zn(s) + Ag2O(s) + H2O(l) \(\rightleftharpoons\) 2Ag(s) + Zn2+(aq) + 2OH\(-\)(aq)
If half cell potentials are
Zn2+(aq) + 2e\(-\) \(\to\) Zn(s);  Eo = \(-\)0.76 V
Ag2O(s) + H2O(l) + 2e...

At 25oC molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm\(-\)1 cm2 mol\(-\)1 and at infinite dilution its molar conductance is 238 ohm\(-\)1 cm2 mol\(-\)1. The degree of ionisation of ammonium hydroxide at t...

Limiting molar conductivity of NH4OH
\(\left[ {} \right.\)i.e.  \(\Lambda _{m\left( {N{H_4}OH} \right)}^0\)\(\left. {} \right]\) is equal to

The Gibb's energy for the decomposition of Al2O3 at 500oC is as follows
\({2 \over 3}\) Al2O3 \(\to\) \({4 \over 3}\) Al + O2
\(\Delta\)rG = +960 kJ mol\(-\)1
The potential difference needed for the electrolytic reduction of aluminium ...

Molar conductivities \(\left( {\Lambda _m^o} \right)\) at infinite dilution of NaCl, Hcl and CH3COONa are 126.4, 425.9 and 91.0 S cm2 mol\(-\)1 respectively. \(\left( {\Lambda _m^o} \right)\) for CH3COOH will be

Standard reduction potentials of the half reactions are given below :
F2(g) + 2e\(-\) \(\to\) 2F\(-\)(aq) ;   Eo = + 2.85 V
Cl2(g) + 2e\(-\) \(\to\) 2Cl\(-\)(aq) ;   Eo = + 1.36 V
Br2(l) + 2e\(-\) \(\to\) 2Br\(-\)(aq) ;   Eo = ...

Standard electrode potential for Sn4+/Sn2+ couple is + 0.15 V and that for the Cr3+/Cr couple is \(-\) 0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be

The electrode potentials for Cu2+(aq) + e\(-\) \(\to\) Cu+(aq) and Cu+(aq) + e\(-\) \(\to\) Cu(s) are + 0.15 V and + 0.50 V respectively. The value of Eocu2+/cu will be

Standard electrode potential of three metals X, Y and Z are \(-\)1.2 V, + 0.5 V and \(-\) 3.0 V respectively. The reducing power of these metals will be

A solution contains Fe2+, Fe3+ and I\(-\) ions. This solution was treated with iodine at 35oC. Eo for Fe3+/Fe2+ is + 0.77 V and Eo for I2/2I\(-\) = 0.536 V.
The favourable redox reaction is

An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to