Redox Reactions and Electrochemistry

Consider the following compounds : \(\underline{\mathrm{K}}\mathrm{O_2}\), \(\mathrm{H_2}\underline{\mathrm{O}}_2\) and \(\mathrm{H_2}\underline{\mathrm{S}}\mathrm{O_4}\).

The oxidation states of the underlined elements in them are, respectively,

If the molar conductivity (\(\Lambda_m\)) of a 0.050 mol \(\mathrm{L^{-1}}\) solution of a monobasic weak acid is 90 S \(\mathrm{cm^2\,mol^{-1}}\), its extent (degree) of dissociation will be

[Assume \(\Lambda^\circ_+ = 349.6\) S \(\mathrm{cm^2\,mol^{-1}}\) and \(\Lambda^\circ_- = 50.4\) S \(\mathrm{cm^2\,mol^{-1}}\).]

Which reaction is NOT a redox reaction?

Match List I with List II.

List I (Conversion): A. 1 mol of \(H_2O\) to \(O_2\) B. 1 mol of \(MnO_4^-\) to \(Mn^{2+}\) C. 1.5 mol of Ca from molten \(CaCl_2\) D. 1 mol of FeO to \(Fe_2O_3\)

List II (Number of Faraday required): I. 3F II. 2F III. 1F IV. 5F

Choose the correct answer from the options given below:

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 Cu : 63 g \(mol^{-1}\), 1F = 96487 C)

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : In equation \(\Delta_r G = -nFE_{cell}\), value of \(\Delta_r G\) depends on n.

Reasons R : \(E_{cell}\) is an intensive property and \(\Delta_r G\) is an extensive property.

In the light of the above statements, choose the correct answer from the options given below :

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

On balancing the given redox reaction,

\(a\,\mathrm{Cr_2O_7^{2-}} + b\,\mathrm{SO_3^{2-}(aq)} + c\,\mathrm{H^+(aq)} \rightarrow 2a\,\mathrm{Cr^{3+}(aq)} + b\,\mathrm{SO_4^{2-}(aq)} + \dfrac{c}{2}\mathrm{H_2O}(\ell)\)

the coefficients a, b and c are found to be, respectively -

At 298 K, the standard electrode potentials of \(Cu^{2+}/Cu\), \(Zn^{2+}/Zn\), \(Fe^{2+}/Fe\) and \(Ag^+/Ag\) are 0.34 V, \(-0.76\) V, \(-0.44\) V and 0.80 V, respectively.

On the basis of standard electrode potential, predict which of the following reaction can not occur ?

Given below are half cell reactions :

\(MnO_4^- + 8H^+ + 5e^- \to Mn^{2+} + 4H_2O\),

\(E^\circ_{Mn^{2+}/MnO_4^-} = -1.510\) V

\(\frac{1}{2}O_2 + 2H^+ + 2e^- \to H_2O\),

\(E^\circ_{O_2/H_2O} = +1.223\) V

Will the permanganate ion, \(MnO_4^-\) liberate \(O_2\) from water in the presence of an acid ?

Find the emf of the cell in which the following reaction takes place at 298 K

\(Ni(s) + 2Ag^+ (0.001\ M) \to Ni^{2+} (0.001\ M) + 2Ag(s)\)

(Given that \(E^\circ_{cell} = 10.5\) V, \(\frac{2.303\,RT}{F} = 0.059\) at 298 K)

The molar conductance of NaCl, HCl and \(CH_3COONa\) at infinite dilution are 126.45, 426.16 and 91.0 S cm\(^2\) mol\(^{-1}\) respectively. The molar conductance of \(CH_3COOH\) at infinite dilution is. Choose the right option for your answer.

Which of the following reactions is the metal displacement reaction ? Choose the right option.

The molar conductivity of 0.007 M acetic acid is 20 S cm\(^2\) mol\(^{-1}\). What is the dissociation constant of acetic acid ? Choose the correct option.

\(\Lambda^\circ_{H^+} = 350\) S cm\(^2\) mol\(^{-1}\), \(\Lambda^\circ_{CH_3COO^-} = 50\) S cm\(^2\) mol\(^{-1}\)

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 CaCl\(_2\) (Atomic mass of Ca = 40 g mol\(^{-1}\)) is :

What is the change in oxidation number of carbon in the following reaction ?

CH\(_4\)(g) + 4Cl\(_2\)(g) \(\rightarrow\) CCl\(_4\)(l) + 4HCl(g)

Which of the following reactions are disproportionation reaction ?

(a) \(2Cu^{+} \to Cu^{2+} + Cu^{0}\)

(b) \(3MnO_4^{2-} + 4H^{+} \to 2MnO_4^{-} + MnO_2 + 2H_2O\)

(c) \(2KMnO_4 \xrightarrow{\Delta} K_2MnO_4 + MnO_2 + O_2\)

(d) \(2MnO_4^{-} + 3Mn^{2+} + 2H_2O \to 5MnO_2 + 4H^{\oplus}\)

Select the correct option from the following :

For the cell reaction

\(2Fe^{3+}(aq) + 2I^{-}(aq) \to 2Fe^{2+}(aq) + I_2(aq)\)

\(E^{\ominus}_{cell} = 0.24\) V at 298 K. The standard Gibbs energy (\(\Delta_rG^{\ominus}\)) of the cell reaction is :

[Given that Faraday constant F = 96500 C mol\(^{-1}\)]

For a cell involving one electron \(E^{\ominus}_{cell} = 0.59\) V at 298 K, the equilibrium constant for the cell reaction is :

[Given that \(\frac{2.303\,RT}{F} = 0.059\) V at T = 298 K]

The correct order of N-compounds in its decreasing order of oxidation states is

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

BrO\(_4^-\) \(\xrightarrow{1.82\ V}\) BrO\(_3^-\) \(\xrightarrow{1.5\ V}\) HBrO \(\xrightarrow{1.595\ V}\) Br\(_2\) \(\xrightarrow{1.0652\ V}\) Br\(^-\)

Then the species undergoing disproportionation is

For the redox reaction

MnO\(_4^-\) + C\(_2\)O\(_4^{2-}\) + H\(^+\) \(\longrightarrow\) Mn\(^{2+}\) + CO\(_2\) + H\(_2\)O

the correct coefficients of the reactants for the balanced equation are

(columns: MnO\(_4^-\), C\(_2\)O\(_4^{2-}\), H\(^+\))

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 of \(ZnSO_4\) is changed to 1.0 M and that of \(CuSO_4\) changed to 0.01 M, the emf changes to \(E_2\). From the followings, which one is the relationship between \(E_1\) and \(E_2\) ? (Given, \(\frac{RT}{F} = 0.059\))

Ionic mobility of which of the following alkali metal ions is lowest when aqueous solution of their salts are put under an electric field ?

The pressure of \(H_2\) required to make the potential of \(H_2\) - electrode zero in pure water at 298 K is :

The number of electrons delivered at the cathode during electrolysis by a current of 1 ampere in 60 seconds is (charge on electron = \(1.60\times10^{-19}\) C)

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

The molar conductivity of a [obscured] solution of \(AgNO_3\) with electrolytic conductivity of \(5.76\times10^{-3}\) 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 \(E^\circ_{cell}\) for a given reaction has a negative value, which of the following gives the correct relationships for the values of \(\Delta G^\circ\) and \(K_{eq}\)?