NCERT solutions for Chemistry [English] Class 12 chapter 3 - Electrochemistry [Latest edition]

How would you determine the standard electrode potential of the system $$\mathrm{Mg}{\phantom{A}}^{2+}|\mathrm{Mg}$$?

Can you store copper sulphate solutions in a zinc pot?

Consult the table of standard electrode potentials and suggest three substances that can oxidise ferrous ions under suitable conditions.

Calculate the potential of hydrogen electrode in contact with a solution whose pH is 10.

Calculate the emf of the cell in which the following reaction takes place: 

$$\mathrm{Ni}{\phantom{A}}_{(\mathrm{s})}+2\mathrm{Ag}{\phantom{A}}^{+}(0.002\mathrm{M})⟶\mathrm{Ni}{\phantom{A}}^{2+}(0.160\mathrm{M})+2\mathrm{Ag}{\phantom{A}}_{(\mathrm{s})}$$

Given that $$\mathrm{E}{\phantom{A}}_{\mathrm{cell}}^{\mathrm{\Theta }}$$ = 1.05 V

The cell in which the following reactions occurs: $$2\mathrm{Fe}{\phantom{A}}_{(\mathrm{aq})}^{3+}+2\mathrm{I}{\phantom{A}}_{(\mathrm{aq})}^{-}⟶2\mathrm{Fe}{\phantom{A}}_{(\mathrm{aq})}^{2+}+\mathrm{I}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{s})}$$ has $$\mathrm{E}{\phantom{A}}_{\mathrm{cell}}^{\mathrm{\Theta }}$$ = 0.236 V at 298 K. Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.

The molar conductivity of 0.025 mol L⁻¹ methanoic acid is 46.1 S cm² mol⁻¹. Calculate its degree of dissociation and dissociation constant. Given $$\mathrm{\lambda }{\phantom{A}}_{({\mathrm{H}}^{+})}^0$$ = 349.6 S cm² mol⁻¹ and $$\mathrm{\lambda }{\phantom{A}}_{({\mathrm{HCOO}}^{-})}^0$$ = 54.6 S cm² mol⁻¹.

If a current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons would flow through the wire?

Suggest a list of metals that are extracted electrolytically.

Consider the reaction: $$\mathrm{Cr}{\phantom{A}}_2\mathrm{O}{\phantom{A}}_7^{2-}+14\mathrm{H}{\phantom{A}}^{+}+6\mathrm{e}{\phantom{A}}^{-}⟶2\mathrm{Cr}{\phantom{A}}^{3+}+7\mathrm{H}{\phantom{A}}_2\mathrm{O}$$

What is the quantity of electricity in coulombs needed to reduce 1 mol of  $$\mathrm{Cr}{\phantom{A}}_2\mathrm{O}{\phantom{A}}_7^{2-}$$?

Write the chemistry of recharging the lead storage battery, highlighting all the materials that are involved during recharging.

Suggest two materials other than hydrogen that can be used as fuels in fuel cells.

Explain how rusting of iron is envisaged as setting up of an electrochemical cell.

Arrange the following metals in the order in which they displace each other from the solution of their salts.

$$\mathrm{Al},\mathrm{Cu},\mathrm{Fe},\mathrm{Mg}$$ and $$\mathrm{Zn}$$

Given the standard electrode potentials,

$$\mathrm{K}{\phantom{A}}^{+}/\mathrm{K}$$ = −2.93 V, $$\mathrm{Ag}{\phantom{A}}^{+}/\mathrm{Ag}$$ = 0.80 V,

$$\mathrm{Hg}{\phantom{A}}^{2+}/\mathrm{Hg}$$ = 0.79 V

$$\mathrm{Mg}{\phantom{A}}^{2+}/\mathrm{Mg}$$ = −2.37 V, $$\mathrm{Cr}{\phantom{A}}^{3+}/\mathrm{Cr}$$ = −0.74 V

Arrange these metals in their increasing order of reducing power.

Depict the galvanic cell in which the reaction $$\mathrm{Zn}(\mathrm{s})+2\mathrm{Ag}{\phantom{A}}^{+}(\mathrm{aq})⟶\mathrm{Zn}{\phantom{A}}^{2+}(\mathrm{aq})+2\mathrm{Ag}(\mathrm{s})$$ takes place. Further show:

1. Which of the electrode is negatively charged?
2. The carriers of the current in the cell.
3. Individual reaction at each electrode.

Calculate the standard cell potential of a galvanic cell in which the following reaction takes place:

$$2\mathrm{Cr}{\phantom{A}}_{(\mathrm{s})}+3\mathrm{Cd}{\phantom{A}}_{(\mathrm{aq})}^{2+}⟶2\mathrm{Cr}{\phantom{A}}_{(\mathrm{aq})}^{3+}+3\mathrm{Cd}$$

Calculate the Δ_rG^Θ and equilibrium constant of the reaction.

Write the Nernst equation and emf of the following cell at 298 K:

$$\mathrm{Mg}{\phantom{A}}_{(\mathrm{s})}|\mathrm{Mg}{\phantom{A}}^{2+}(0.001\mathrm{M})||\mathrm{Cu}{\phantom{A}}^{2+}(0.0001\mathrm{M})|\mathrm{Cu}{\phantom{A}}_{(\mathrm{s})}$$

In the button cells widely used in watches and other devices, the following reaction takes place:

$$\mathrm{Zn}{\phantom{A}}_{(\mathrm{s})}+\mathrm{Ag}{\phantom{A}}_2\mathrm{O}{\phantom{A}}_{(\mathrm{s})}+\mathrm{H}{\phantom{A}}_2\mathrm{O}{\phantom{A}}_{(\mathrm{l})}⟶\mathrm{Zn}{\phantom{A}}_{(\mathrm{aq})}^{2+}+2\mathrm{Ag}{\phantom{A}}_{(\mathrm{s})}+2\mathrm{OH}{\phantom{A}}_{(\mathrm{aq})}^{-}$$

Determine Δ_rG^Θ and E^Θ for the reaction.

Define conductivity for the solution of an electrolyte.

The conductivity of 0.20 M solution of $$\mathrm{KCl}$$ at 298 K is 0.0248 S cm⁻¹. Calculate its molar conductivity.

Predict the product of electrolysis in the following:

An aqueous solution of $$\mathrm{CuCl}{\phantom{A}}_2$$ with platinum electrodes.

The resistance of a conductivity cell containing 0.001M $$\mathrm{KCl}$$ solution at 298 K is 1500 Ω. What is the cell constant if the conductivity of 0.001M $$\mathrm{KCl}$$ solution at 298 K is 0.146 × 10⁻³ S cm⁻¹.

The conductivity of sodium chloride at 298 K has been determined at different concentrations and the results are given below:

Calculate ${\displaystyle {\wedge }_{\text{m}}}$for all concentrations and draw a plot between ${\displaystyle {\wedge }_{\text{m}}}$and ${\displaystyle {\text{c}}^{\frac{1}{2}}}$. Find the value of ${\displaystyle {\wedge }_{\text{m}}^0}$.

Conductivity of 0.00241 M acetic acid is 7.896 × 10⁻⁵ S cm⁻¹. Calculate its molar conductivity and if ${\displaystyle {\wedge }_{\text{m}}^0}$ for acetic acid is 390.5 S cm² mol⁻¹, what is its dissociation constant?

How much charge is required for the following reduction:

1 mol of $$\mathrm{Al}{\phantom{A}}^{3+}$$ to $$\mathrm{Al}$$?

How much charge is required for the following reduction:

1 mol of $$\mathrm{Cu}{\phantom{A}}^{2+}$$ to $$\mathrm{Cu}$$?

How much charge is required for the following reduction:

1 mol of $$\mathrm{MnO}{\phantom{A}}_4^{-}$$ to $$\mathrm{Mn}{\phantom{A}}^{2+}$$?

How much electricity is required in coulomb for the oxidation of 1 mol of $$\mathrm{H}{\phantom{A}}_2\mathrm{O}$$ to $$\mathrm{O}{\phantom{A}}_2$$?

How much electricity is required in coulomb for the oxidation of 1 mol of $$\mathrm{FeO}$$ to $$\mathrm{Fe}{\phantom{A}}_2\mathrm{O}{\phantom{A}}_3$$?

A solution of $$\mathrm{Ni}(\mathrm{NO}{\phantom{A}}_3){\phantom{A}}_2$$ is electrolysed between platinum electrodes using a current of 5 amperes for 20 minutes. What mass of $$\mathrm{Ni}$$ is deposited at the cathode?

Three electrolytic cells A, B, C containing solutions of $$\mathrm{ZnSO}{\phantom{A}}_4$$, $$\mathrm{AgNO}{\phantom{A}}_3$$ and $$\mathrm{CuSO}{\phantom{A}}_4$$, respectively, are connected in series. A steady current of 1.5 amperes was passed through them until 1.45 g of silver deposited at the cathode of cell B. How long did the current flow? What mass of copper and zinc were deposited?

Using the standard electrode potentials, predict if the reaction between the following is feasible:

$$\mathrm{Fe}{\phantom{A}}_{(\mathrm{aq})}^{3+}$$ and $$\mathrm{I}{\phantom{A}}_{(\mathrm{aq})}^{-}$$

Using the standard electrode potentials, predict if the reaction between the following is feasible:

$$\mathrm{Ag}{\phantom{A}}_{(\mathrm{aq})}^{+}$$ and $$\mathrm{Cu}{\phantom{A}}_{(\mathrm{s})}$$

Using the standard electrode potentials, predict if the reaction between the following is feasible:

$$\mathrm{Fe}{\phantom{A}}_{(\mathrm{aq})}^{3+}$$ and $$\mathrm{Br}{\phantom{A}}_{(\mathrm{aq})}^{-}$$

Using the standard electrode potentials, predict if the reaction between the following is feasible:

$$\mathrm{Ag}{\phantom{A}}_{(\mathrm{s})}$$ and $$\mathrm{Fe}{\phantom{A}}_{(\mathrm{aq})}^{3+}$$

Using the standard electrode potentials, predict if the reaction between the following is feasible:

$$\mathrm{Br}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{aq})}$$ and $$\mathrm{Fe}{\phantom{A}}_{(\mathrm{aq})}^{2+}$$ 

Predict the product of electrolysis in the following:

An aqueous solution of $$\mathrm{AgNO}{\phantom{A}}_3$$ with silver electrodes.

Predict the product of electrolysis in the following:

An aqueous solution of $$\mathrm{AgNO}{\phantom{A}}_3$$ with platinum electrodes.

Predict the product of electrolysis in the following:

A dilute solution of $$\mathrm{H}{\phantom{A}}_2\mathrm{SO}{\phantom{A}}_4$$ with platinum electrodes.