STANDARD Chemistry Electrochemistry Class 12 Questions

The cell reaction of the galvanic cell : Cu(s)|Cu²⁺(aq)||Hg²⁺(aq)|Hg(l) is

Which of the following reactions is possible at anode?

For the galvanic cell, Cu|Cu²⁺||Ag⁺|Ag. Which of the following observations is not correct?

The standard reduction potential for the half-cell reaction, Cl₂ + 2e⁻ → 2Cl⁻ will be (Pt²⁺ + 2Cl⁻ → Pt + Cl₂, E° cell = -0.15 V; Pt²⁺ + 2e⁻ → Pt, E° = 1.20 V)

In a cell reaction, Cu(s) + 2Ag⁺(aq) → Cu²⁺(aq) + 2Ag(s) E° cell = +0.46 V. If the concentration of Cu²⁺ ions is doubled then E° cell will be

Zn gives hydrogen with H₂SO₄ and HCl but not with HNO₃ because

E°_{Mn³⁺/Mn²⁺} is highly positive than that of E°_{Cr³⁺/Cr²⁺} or E°_{Fe³⁺/Fe²⁺} because

Fluorine is the best oxidising agent because it has

The correct Nernst equation for the given cell Pt(s)|Br₂|Br⁻(M)||H⁺(M)|H₂(g) (1 bar)|Pt(s) is

What will be the emf of the following concentration cell at 25°C? Ag(s)|AgNO₃(0.01 M)||AgNO₃ (0.05M)|Ag(s)

What will be the reduction potential for the following half-cell reaction at 298 K? (Given : [Ag⁺] = 0.1 M and E°_cell = +0.80 V)

Cell reaction is spontaneous, when

The Gibbs energy for the decomposition of Al₂O₃ at 500°C is as follows : 2/3Al₂O₃ → 4/3Al + O₂ ; ΔG = +966 kJ/mol. The potential difference needed for electrolytic reduction of Al₂O₃ at 500°C is at least

For the cell reaction : 2Cu⁺(aq) → Cu(s) + Cu²⁺(aq), the standard cell potential is 0.36V. The equilibrium constant for the reaction is

Given below are few statements regarding electrode potentials. Mark the correct statements. (i) The potential associated with each electrode is known as electrode potential. (ii) A negative E° means that the redox couple is a stronger reducing agent than H⁺/H₂ couple. (iii) A positive E° means that the redox couple is a weaker reducing agent than H⁺/H₂ couple.

Which of the following will act as cathode when connected to standard hydrogen electrode which has E° value given as zero? (i) Zn²⁺/Zn, E° = −0.76 V (ii) Cu²⁺/Cu, E° = +0.34 V (iii) Al³⁺/Al, E° = −1.66 V (iv) Hg²⁺/Hg, E° = +0.885 V

Which of the following is not a correct statement about electrochemical series of reduction potentials?

Arrange the following metals in which they displace each other from the solutions of their salts in decreasing order. Al, Cu, Fe, Mg and Zn E_{Al^{3+}/Al} = -1.66 V, E_{Cu^{2+}/Cu} = +0.34 V, E_{Fe^{2+}/Fe} = -0.44 V, E_{Mg^{2+}/Mg} = -2.36 V and E_{Zn^{2+}/Zn} = -0.76 V

E° values for the half cell reactions are given below: Cu²⁺ + e⁻ → Cu⁺ ; E° = 0.15 V Cu²⁺ + 2e⁻ → Cu ; E° = 0.34 V Which will be the E° of the half-cell ; Cu⁺ + e⁻ → Cu?

G° for the reaction, Cu²⁺ + Fe → Fe²⁺ + Cu is (Given : E°_{Cu²⁺/Cu} = +0.34 V, E°_{Fe²⁺/Fe} = -0.44 V)

E° values of some redox couples are given below. On the basis of these values choose the correct option. E° values : Br₂/Br⁻ = +1.90 ; Ag⁺/Ag(s) = +0.80 ; Cu²⁺/Cu(s) = +0.34 ; I₂(s)/I⁻ = +0.54 V.

Using the following Latimer diagram for bromine, the species undergoing disproportionation is

Units of the properties measured are given below. Which of the properties has not been matched correctly?

Molar conductivity of 0.15 M solution of KCl at 298 K, if its conductivity is 0.0152 S cm⁻¹, will be

The specific conductance of a saturated solution of AgCl at 25°C is 1.821 × 10⁻⁵ mho cm⁻¹. What is the solubility of AgCl in water (in g L⁻¹), if limiting molar conductivity of AgCl is 130.26 mho cm² mol⁻¹?

Specific conductance of 0.1 M NaCl solution is 1.01 × 10⁻² ohm⁻¹ cm⁻¹. Its molar conductance in ohm⁻¹ cm² mol⁻¹ is

The variation in Λₘ with concentration for a strong electrolyte can be represented by the equation, Λₘ = Λₘ° – A√C. The value of constant A for a given solvent and temperature depends upon the type of electrolyte i.e., cations and anions produced on dissociation of electrolyte in the solution. Which of the following statements is correct regarding variations of molar conductivity with concentration?

When water is added to an aqueous solution of an electrolyte, what is the change in specific conductivity of the electrolyte?

Mark the correct choice of electrolytes represented in the graph.

For which case Λ values vs √c shows a straight line?

Limiting molar conductivity of NaBr is

What will be the molar conductivity of Al³⁺ ions at infinite dilution if molar conductivity of Al₂(SO₄)₃ is 858 S cm² mol⁻¹ and ionic conductance of SO₄²⁻ is 160 S cm² mol⁻¹ at infinite dilution?

Molar conductivity of 0.025 mol L⁻¹ methanoic acid is 46.1 S cm² mol⁻¹, the degree of dissociation and dissociation constant will be (Given : λ°_H⁺ = 349.6 S cm² mol⁻¹ and λ°_HCOO⁻ = 54.6 S cm² mol⁻¹)

Match the column I with column II and mark the appropriate choice.

How long would it take to deposit 50 g of Al from an electrolytic cell containing Al₂O₃ using a current of 105 ampere?

The charge required for reducing 1 mole of MnO₄⁻ to Mn²⁺ is

How much electricity in terms of Faraday is required to produce 100 g of Ca from molten CaCl₂?

How many coulombs of electricity is required to reduce 1 mole of Cr₂O₇²⁻ in acidic medium?

An electric charge of 5 Faradays is passed through three electrolytes AgNO₃, CuSO₄ and FeCl₃ solution. The grams of each metal liberated at cathode will be:

Which of the following statements is not correct?

How much metal will be deposited when a current of 12 ampere with 75% efficiency is passed through the cell for 3 h? (Given: z = 4 × 10⁻⁴)

During electrolysis of a solution of AgNO₃, 9650 coulombs of charge is passed through the solution. What will be the mass of silver deposited on the cathode?

How many moles of Pt may be deposited on the cathode when 0.80 F of electricity is passed through a 1.0 M solution of Pt⁴⁺?

If 54 g of silver is deposited during an electrolysis reaction, how much aluminium will be deposited by the same amount of electric current?

Which of the following statements is true?

Match the Column-I with Column-II and mark the appropriate choice.

An electrochemical cell can behave like an electrolytic cell when

The quantity of charge required to obtain one mole of aluminium from Al₂O₃ is

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

The EMF of a cell corresponding to the reaction: Zn(s) + 2H⁺(aq) → Zn²⁺(aq) (0.1 M) + H₂(g) (1 atm) is 0.28 volt at 15°C. The pH of the solution at the hydrogen electrode is (Given: E°_{Zn²⁺/Zn} = -0.76 volt; E°_{H⁺/H₂} = 0 volt)