Electrochemistry Questions

If 9 g H₂O is electrolysed completely with current efficiency of 50%, then-

A graph of molar conductivity of three electrolytes (NaCl, HCl and NH₄OH) is plotted against √C. Which option is correct?

The passage of electricity through certain electrolyte results in liberation of H₂ gas at the cathode. The electrolyte could be-

When copper sulphate solution is electrolysed in a copper voltameter for 30 s, m gram of copper was deposited. Time-current graph is given. The electrochemical equivalent of copper from above plot will be-

Below plot represents variation of molar conductance against √C. Select the correct option.

In an electrolytic cell 1 L of 0.1 M aqueous MnO4²⁻ is converted to MnO4⁻. What statement is correct?

The standard reduction potential E° for OCl⁻/Cl⁻ = 0.86 V and Cl⁻/½Cl₂ = −1.10 V The E° value of OCl⁻/½Cl₂ will be-

A fuel cell involves combustion of butane at 1 atm and 298 K, C₄H₁₀ + 13/2 O₂ → 4CO₂ + 5H₂O ΔG° = −2746 kJ mol⁻¹ What is E°cell?

Equivalent conductance of 0.1 M HA (weak acid) is 10 S cm² equiv⁻¹ and at infinite dilution is 200 S cm² equiv⁻¹. Hence pH of HA solution is-

The EMF of the cell Ni | Ni²⁺ || Cu²⁺ | Cu is 0.59 V. E°(Cu²⁺/Cu) = +0.34 V The standard reduction potential of nickel electrode is-

A current of 2 A when passed for 5 h through a molten salt deposits 22.2 g of metal of atomic mass 177. The oxidation state of the metal salt is-

The equivalent conductance of an infinitely dilute solution of NH₄Cl is 150 and ionic conductances of OH⁻ and Cl⁻ ions are 198 and 76 respectively. If the equivalent conductance of 0.01 N solution of NH₄OH is 9.6, what is its degree of dissociation?

In electroplating, m g of silver is deposited when 4 A current flows for 2 min. The amount of silver deposited by 6 A current flowing for 40 sec will be-

Salts of A (atomic mass 15), B (atomic mass 27) and C (atomic mass 48) were electrolysed using same amount of charge. When 4.5 g of A was deposited, masses of B and C deposited were 2.7 g and 9.6 g. The valencies of A, B and C respectively are-

The reaction for the cell, Zn | Zn²⁺(1.0 M) || Cd²⁺(1.0 M) | Cd is-

The value of equilibrium constant for a feasible cell reaction is-

Which one of the following does not hold good for S.H.E.-

The function of the salt bridge is to-

An example of a simple fuel cell is-

In an electrochemical cell-

Which is correct representation for a cell at equilibrium-

The thermodynamic efficiency of a fuel cell is given by-

The following facts are available: 2A⁻ + B₂ → 2B⁻ + A₂ 2C⁻ + B₂ → No reaction 2D⁻ + A₂ → 2A⁻ + D₂ Which statement is correct-

Four colourless salt solutions are placed in separate test tubes and a strip of copper is placed in each. Which solution finally turns blue-

E°Al³⁺/Al = −1.66 V and Ksp of Al(OH)₃ = 1 × 10⁻³³. Reduction potential of the couple at pH = 14 is-

The reduction potential of hydrogen electrode at pH = 10 will be-

The solution of nickel sulphate in which nickel rod is dipped is diluted to 10 times. The reduction potential of nickel-

For the cell prepared from electrodes A and B A : Cr₂O₇²⁻ / Cr³⁺ ; E°red = +1.33 V B : Fe³⁺ / Fe²⁺ ; E°red = +0.77 V Which statement(s) is/are correct-

For I₂ + 2e⁻ → 2I⁻ E°red = +0.54 V and 2Br⁻ → Br₂ + 2e⁻ E°ox = +1.09 V For Fe → Fe²⁺ + 2e⁻ E°ox = +0.44 V Which reaction is non-spontaneous?

For the cell reaction, Cu²⁺(C₁) + Zn(s) ⇌ Zn²⁺(C₂) + Cu(s) the change in free energy at a given temperature is a function of-

Zn + Cu²⁺ ⇌ Cu + Zn²⁺ , Q = [Zn²⁺]/[Cu²⁺] Variation of Ecell with logQ is shown. OA = 1.10 V. Ecell will be 1.1591 V when-

For a reaction A(s) + 2B⁺ → A²⁺ + 2B KC has been found to be 10¹². The E°cell is-

The e.m.f. of the cell involving the reaction 2Ag⁺ + H₂ → 2Ag + 2H⁺ is 0.80 V. The standard oxidation potential of silver electrode is-

The standard reduction potential of Pb and Zn electrodes are –0.126 V and –0.763 V respectively. The e.m.f. of the cell Zn | Zn²⁺(0.1 M) || Pb²⁺(1 M) | Pb is-

Point out the correct statement about Zn–CuSO₄ cell-

In the given arrangement, on pressing the key, the-

Red hot carbon will remove oxygen from the oxides XO and YO but not from ZO. Y will remove oxygen from XO. Use this evidence to deduce the order of activity of the three metals X, Y and Z, putting the most reactive first-

In the arrangement shown, the arrow represents-

The electrode potential measures the-

A student made the following observations: (i) Clean copper metal did not react with 1 M Pb(NO₃)₂ solution (ii) Clean lead metal dissolved in 1 M AgNO₃ solution and crystals of Ag appeared (iii) Clean silver metal did not react with 1 M Cu(NO₃)₂ solu

Given Ag⁺/Ag = +0.80 V Co²⁺/Co = –0.28 V Cu²⁺/Cu = +0.34 V Zn²⁺/Zn = –0.76 V The most reactive metal which displaces other metals from their salt solution is-

Which one will liberate Br₂ from KBr-

Which of the following solution can be safely stored in a copper vessel-

When a copper wire is immersed in a solution of AgNO₃, the colour of the solution becomes blue because copper-

Consider the following electrolytes: 1. AgNO₃ 2. CuSO₄ 3. AlCl₃ 4. Bi₂(SO₄)₃ The quantity of electricity needed to electrolyse separately 1 M solutions of these electrolytes will be-

The reduction potential of the two half cell reactions are PbSO₄ + 2e⁻ → Pb + SO₄²⁻ E° = –0.31 V Ag⁺ + e⁻ → Ag E° = +0.80 V The feasible reaction will be-

20 g of chlorine are evolved in 6 hour from sodium chloride solution by the current of-

The weight ratio of Al and Ag deposited using the same quantity of current is-

A certain current liberates 0.500 g of H₂ in 2.00 h. How many gram of oxygen can be liberated by the same current in the same time?

Number of faraday required to liberate 8 g of H₂ is-