Tamil Nadu Board Samacheer Kalvi solutions for Class 12th Chemistry Volume 1 and 2 Answers Guide chapter 9 - Electro Chemistry [Latest edition]

The number of electrons that have a total charge of 9650 coulombs is ____________.

Consider the following half cell reactions:

\[\ce{Mn^{2+} + 2e^- -> Mn}\] E⁰ = –1.18 V

\[\ce{Mn^{2+} -> Mn^{2+} + e^-}\] E⁰ = –1.51 V

The E⁰ for the reaction \[\ce{3Mn^{2+} -> Mn + 2Mn^{3+}}\], and the possibility of the forward reaction are respectively.

The button cell used in watches functions as follows.

\[\ce{Zn_{(s)} + Ag2O_{(s)} + H2O_{(l)} ⇌ 2Ag_{(s)} + Zn^{2+}_{( aq)} + 2OH^-_{( aq)}}\] the half cell potentials are \[\ce{Ag2O_{(s)} + H2O_{(l)} + 2e^- -> 2Ag_{(s)} + 2OH^-_{( aq)}}\] E⁰ = 0.34 V The cell potential will be

The molar conductivity of a 0.5 mol dm⁻³ solution of AgNO₃ with electrolytic conductivity of 5.76 × 10⁻³ S cm⁻¹ at 298 K is ____________.

Calculate \[\ce{Λ^∘_{HOAC}}\] using appropriate molar conductances of the electrolytes listed above at infinite dilution in water at 25°C.

Faradays constant is defined as ____________.

How many faradays of electricity are required for the following reaction to occur

\[\ce{MnO^-_4 -> Mn^2+}\]

A current strength of 3.86 A was passed through molten Calcium oxide for 41minutes and 40 seconds. The mass of Calcium in grams deposited at the cathode is (atomic mass of Ca is 40g/mol and 1F = 96500 C).

During electrolysis of molten sodium chloride, the time required to produce 0.1 mole of chlorine gas using a current of 3A is ___________.

The number of electrons delivered at the cathode during electrolysis by a current of 1A in 60 seconds is ____________.
(charge of electron = 1.6 × 10⁻¹⁹ C)

Which of the following electrolytic solution has the least specific conductance?

While charging lead storage battery

Among the following cells

I) Leclanche cell

II) Nickel – Cadmium cell

III) Lead storage battery

IV) Mercury cell

Primary cells are:

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

Assertion: pure iron when heated in dry air is converted with a layer of rust.

Reason: Rust has the compositionFe₃O₄.

In \[\ce{H2 - O2}\] fuel cell the reaction occurs at cathode is:

The equivalent conductance of `"M"/36` solution of a weak monobasic acid is 6 mho cm² equivalent⁻¹ and at infinite dilution is 400 mho cm² equivalent⁻¹. The dissociation constant of this acid is ____________.

A conductivity cell has been calibrated with a 0.01 M, 1 : 1 electrolytic solution (specific conductance (κ = 1.25 × 10⁻³ S cm⁻¹) in the cell and the measured resistance was 800 Ω at 25°C. The cell constant is, ____________.

Conductivity of a saturated solution of a sparingly soluble salt AB (1 : 1 electrolyte) at 298 K is 1.85 × 10⁻⁵ S m⁻¹. Solubility product of the salt AB at 298 K `(Λ_"m"^∘)_"AB"` = 14 × 10⁻³ S m² mol⁻¹.

In the electrochemical cell: Zn|ZnSO₄ (0.01 M)||CuSO₄ (1.0 M)|Cu, the emf of this Daniel cell is E₁. When the concentration of ZnSO₄ is changed to 1.0 M and that CuSO₄ changed to 0.01 M, the emf changes to E₂. From the above, which one is the relationship between E₁ and E₂?

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

\[\ce{BrO^-_4 ->[1.82 V] BrO^-_3 ->[1.5 V] HBrO ->[1.595 V] Br2 ->[1.0652 V] Br^-}\]

Then the species undergoing disproportionation is

For the cell reaction

\[\ce{2Fe^{3+}_{( aq)} + 2l^-_{( aq)} -> 2Fe^{2+}_{( aq)} + l2_{( aq)}}\]

\[\ce{E^0_{cell}}\] = at 298 K. The standard Gibbs energy (∆G°) of the cell reactions is:

A certain current liberated 0.504 gm of hydrogen in 2 hours. How many grams of copper can be liberated by the same current flowing for the same time through copper sulphate solution.

A gas X at 1 atm is bubbled through a solution containing a mixture of 1MY⁻ and 1MZ⁻ at 25°C. If the reduction potential of Z > Y > X, then ____________.

Cell equation: \[\ce{A + 2B^- -> A^{2+} + 2B}\]

\[\ce{A^{2+} + 2e^- -> A}\] E⁰ = +0.34 V and log₁₀ k = 15.6 at 300 K for cell reactions find E⁰ for \[\ce{B^+ + e^- -> B}\]

Define anode

Define cathode

Why does the conductivity of a solution decrease on dilution of the solution?

State Kohlrausch law. How is it useful to determine the molar conductivity of weak electrolytes at infinite dilution?

Describe the electrolysis of molten NaCl using inert electrodes.

State Faraday’s Laws of electrolysis.

Describe the construction of Daniel cell. Write the cell reaction.

Why is anode in galvanic cell considered to be negative and cathode positive electrode?

The conductivity of a 0.01 M solution of a 1 : 1 weak electrolyte at 298 K is 1.5 × 10⁻⁴ S cm⁻¹.

i) molar conductivity of the solution

ii) degree of dissociation and the dissociation constant of the weak electrolyte

Given that

\[\ce{λ^∘_{cation}}\] = 248.2 S cm² mol⁻¹

\[\ce{λ^∘_{anion}}\] = 51.8 S cm² mol⁻¹

Which of 0.1 M HCl and 0.1 M KCl do you expect to have greater `Λ_"m"^∘` and why?

Arrange the following solutions in the decreasing order of specific conductance.

i) 0.01 M KCl

ii) 0.005 M KCl

iii) 0.1 M KCl

iv) 0.25 M KCl

v) 0.5 M KCl

Why is AC current used instead of DC in measuring the electrolytic conductance?

0.1 M NaCl solution is placed in two different cells having cell constant 0.5 and 0.25 cm⁻¹ respectively. Which of the two will have a greater value of specific conductance.

A current of 1.608A is passed through 250 mL of 0.5 M solution of copper sulphate for 50 minutes. Calculate the strength of Cu²⁺ after electrolysis assuming volume to be constant and the current efficiency is 100%.

Can Fe³⁺ oxidises bromide to bromine under standard conditions?

Given: \[\ce{E^0_{{Fe^{3+}|Fe^{2+}}}}\] = 0.771 V

\[\ce{E^0_{{Br_{2}|Br^-}}}\] = −1.09 V

Is it possible to store copper sulphate in an iron vessel for a long time?

Given: \[\ce{E^0_{{Cu^{2+}|{Cu}}}}\] = 0.34 V and \[\ce{E^0_{{Fe^{2+}|{Fe}}}}\] = −0.44 V

Two metals M₁ and M₂ have reduction potential values of −xV and +yV respectively. Which will liberate H₂ and H₂SO₄.

Reduction potential of two metals M₁ and M₂ are \[\ce{E^0_{{M_1^{2+}|M_1}}}\] = −2.3 V and \[\ce{E^0_{{M_2^{2+}|M_2}}}\] = 0.2 V. Predict which one is better for coating the surface of iron.
Given: \[\ce{E^0_{{Fe^{2+}|Fe}}}\] = −0.44 V

Calculate the standard emf of the cell: \[\ce{Cd|Cd^{2+}||Cu^{2+}|Cu}\] and determine the cell reaction. The standard reduction potentials of Cu²⁺|Cu and Cd²⁺|Cd are 0.34 V and −0.40 volts respectively. Predict the feasibility of the cell reaction.

In fuel cell H₂ and O₂ react to produce electricity. In the process, H₂ gas is oxidised at the anode and O₂ at cathode. If 44.8 litre of H₂ at 25°C and 1 atm pressure reacts in 10 minutes, what is average current produced? If the entire current is used for electro deposition of Cu from Cu²⁺, how many grams of deposited?

The same amount of electricity was passed through two separate electrolytic cells containing solutions of nickel nitrate and chromium nitrate respectively. If 2.935 g of Ni was deposited in the first cell. The amount of Cr deposited in the another cell?
Given: molar mass of Nickel and chromium are 58.74 and 52 gm⁻¹ respectively.

A copper electrode is dipped in 0.1 M copper sulphate solution at 25°C. Calculate the electrode potential of copper.
[Given: \[\ce{E^0_{{Cu^{2+}|Cu}}}\] = 0.34 V]

For the cell \[\ce{Mg_{(s)}|Mg^{2+}_{( aq)}||Ag^+_{( aq)}|Ag_{(s)}}\], calculate the equilibrium constant at 25°C and maximum work that can be obtained during operation of cell.
Given: \[\ce{E^0_{{Mg^{2+}|Mg}}}\] = −2.37 V and \[\ce{E^0_{{Ag^{+}|Ag}}}\] = 0.80 V

8.2 × 10¹² litres of water is available in a lake. A power reactor using the electrolysis of water in the lake produces electricity at the rate of 2 × 10⁶ Cs⁻¹ at an appropriate voltage. How many years would it like to completely electrolyse the water in the lake? Assume that there is no loss of water except due to electrolysis.

Derive an expression for the Nernst equation.

Write a note on sacrificial protection.

Explain the function of H₂ – O₂ fuel cell.

Ionic conductance at infinite dilution of Al³⁺ and \[\ce{SO^{2-}_4}\] are 189 and 160 mho cm² equiv⁻¹. Calculate the equivalent and molar conductance of the electrolyte Al₂(SO₄)₃ at infinite dilution.