Electrochemistry

CBSE Class 12 Chemistry · 142 board questions from this chapter; 141 listed below, 2022–2026 · 2 of them repeated across years

• Consider the following reaction: Zn_(s)+Ag_2 O_(s)+H_2 O(l) → Zn_(aq)^2++2 Ag_(s)+2 OH_(aq)^- Given: E^0_Ag^+ / Ag=0.80 V E_Zn^2+…2026
• How many Faradays are required to reduce 1 mol of Cr_2 O_7^2- to Cr^3+ in acidic medium?2026
• What will happen during the electrolysis of aqueous solution of CuCl_2 by using platinum electrodes?2026
• Consider the following cell at 298 K: Mg(s)|Mg^2+(1 · 0 M)||Cu^2+(1 · 0 M)| Cu(s) How can we increase the emf of the cell using…2026
• How the conductivity varies on decreasing concentration for both weak and strong electrolytes?2026
• On electrolysis of very dilute aqueous solution of NaCl using platinum electrodes:2026
• Assertion: E_Mn^2+ / Mn^o value is highly negative. Reason (R): Because Mn^2+ is highly stable due to half-filled 3 d^5…2026
• Name the cell used in hearing aids and watches. Define conductivity. Why is direct current (DC) not used for the measurement of…2026
• Name any two materials other than hydrogen that can be used as fuel in fuel cells. Define molar conductivity.2026
• Name the cell which was used in the Apollo space programme for providing electrical power. Define limiting molar conductivity.2026
• Calculate emf of the following cell at 298 K: Al( s)|Al^3+(aq)(0.1 M) ∥ Ni^2+(aq)(0.01 M)| Ni( s) (Given: E_Ni^2+ / Ni^o=-0.25 V,…2026
• Calculate emf of the following cell at 298 K: Cr(s)|Cr^3+(aq)(0.1 M) ∥ Fe^2+(aq)(0.01 M)| Fe(s) (Given: E_Cr^3+ / Cr^o=-0.74 V,…2026
• Calculate emf of the following cell at 298 K: Zn( s)|Zn^2+(aq)(0.1 M) ∥ Ag^+(aq)(0.01 M)| Ag( s) (Given: E_Zn^2+ / Zn^o=-0.76 V,…2026
• State Kohlrausch's law of independent migration of ions. With the help of a curve, explain why it is not easy to determine Λ_m^°…2026
• Answer the following: (i) Why is the Equilibrium Constant (K_c) related to E_cell^° and not to E_cell? (ii) Two metals 'A' and…2026
• Calculate emf of the following cell at 298 K: Sn|Sn^2+(0.001 M)||H^+(0.01 M)| H_2( g)(1 bar ) ∣ Pt_(s) Given: E^0_Sn^2+ /…2026
• Answer the following questions: Why is direct current (DC) not used to measure the resistance of an ionic solution? Why are the…2026
• Electrochemistry is the study of the relationship between chemical energy and electrical energy. Many spontaneously occurring…2026
• The conductivity of 0.1 mol L^-1 solution of NaC l is 1.06 × 10^-2 S cm^-1. Calculate its molar conductivity and degree of…2026
• (i) Calculate the electrode potential of a half-cell for zinc electrode dipping in 0.01 M ZnSO_4 solution at 25°C. Given: E_Zn^2+…2026
• Calculate emf and Δ G for the following cell at 298 K: Mg( s) / Mg^2+(0.01 M) / / Ag^+(0.001 M) / Ag( s); Given: E_Mg^2+ /…2026
• (i) Calculate E_cell^0 for the following reaction which is at equilibrium: Cu(s)+2 Ag^+(aq) ⇌ Cu^2+(aq)+2 Ag(s) Equilibrium…2026
• The charge required for the reduction of 1 mol of MnO_4^- to MnO_2 is2025
• In an electrochemical cell, the following reaction takes place: 2 Cu^+(aq)+Zn( s) → 2 Cu( s)+Zn^2+(aq); E_cell^°=1 · 28 V As the…2025
• Standard electrode potential for Sn^4+ / Sn^2+ couple is +0.15 V and that for the Cr^3+ / Cr couple is -0.74 V. The two couples…2025
• During electrolysis of dilute H_2 SO_4, using platinum electrodes, the gas evolved at the anode is:2025
• Kohlrausch gave the following relation for strong electrolytes: Λ_m=Λ_m^°-A √C Which of the following equality holds true?2025asked 2×
• A conductivity cell usually consists of two:2025
• The product of the oxidation of I^- with MnO_4^- in alkaline medium is:2025
• In an electrochemical cell, the following reaction takes place: 2 Ag^+(aq)+Mg( s) → 2 Ag( s)+Mg^2+(aq); E_cell^°=2 · 96 V As the…2025
• We cannot measure the resistance of an ionic solution using DC because:2025
• A galvanic cell can behave like an electrolytic cell when2025
• Which of the following cell converts the energy of combustion of fuel into electrical energy?2025
• What amount of electric charge is required for the oxidation of 1 mole of FeO to Fe_2 O_3?2025
• What amount of electric charge is required for the reduction of 1 mole of MnO_4^- into Mn^2+?2025
• Match the type of cell given in Column I with their use given in Column II.2025
• What amount of electric charge is required for the oxidation of 1 mole of H_2 O to O_2?2025
• Assertion: For measuring resistance of an ionic solution an AC source is used. Reason (R): Concentration of ionic solution will…2025
• Assertion: Electrolysis of aqueous NaCl gives H_2 at cathode and Cl_2 at anode. Reason (R): Chlorine has higher oxidation…2025
• Assertion: Cu cannot liberate H_2 on reaction with dilute mineral acids. Reason (R): Cu has positive electrode potential.2025
• Based on the data given above, give plausible reason for the variation of conductivity and molar conductivity with concentration.2025
• Complete and balance the following chemical equations: 2 × 1 8 MnO_4^-+3 S_2 O_3^2-+H_2 O → Cr_2 O_7^2-+3 Sn^2++14 H^+ →2025
• Name and define the cell which was used for providing electric power in the Apollo space programme. Also write its one advantage.2025
• Define fuel cell. Give two advantages of fuel cell over ordinary cell.2025
• Calculate the cell voltage of the voltaic cell which is set up by joining following half-cells at 25^° C: Al / Al^3+(0 · 001 M)…2025
• Calculate Δ_r G^° and log K_C of the reaction: Fe^2+(aq)+Ag^+(aq) → Fe^3+(aq)+Ag(s) Given E_Ag^+ / Ag^°=0.80 V, E_Fe^3+ /…2025
• Calculate Λ^° m for acetic acid and its degree of dissociation (α) if its molar conductivity is 48.1 Ω^-1 cm^2 mol^-1. Given that…2025
• Give reasons: Fuel cells are preferred for production of electrical energy than thermal plants. Iron does not rust even if zinc…2025
• Calculate Δ_r G^° and log K_C of the reaction. 3 2 Cr( s)+3 Cd^2+(aq) → 2 Cr^3+(aq)+3 Cd( s) Given E_Cr^3+ / Cr^°=-0.74 V E_Cd^2+…2025
• State the following: 3 (i) Kohlrausch law of independent migration of ions and (ii) Faraday's first law of electrolysis. Using…2025
• The electrical resistance of a column of 0.05 M NaOH solution of area 0.8 cm^2 and length 40 cm is 5 × 10^3 ohm. Calculate its…2025
• Give reasons for the following: The pH of aqueous NaCl increases when it is electrolysed. Unlike dry cell, mercury cell has a…2025
• Calculate the cell voltage of the voltaic cell which is set up by joining the following half-cells at 25°C: Al / Al^3+(0.001 M)…2025
• Write the name of the cell which is generally used in inverters. Write the reactions taking place at anode and cathode of this…2025
• Calculate the cell voltage of the voltaic cell which is set up by joining the following half-cells at 25°C. Al / Al^3+(0 · 002 M)…2025
• (i) For a galvanic cell, the following half reactions are given. Decide, which will remain as reduction reaction and which will…2025
• (i) Calculate E_cell of a galvanic cell in which the following reaction takes place at 25^° C: Zn( s)+Pb^2+(0 · 02 M) → Zn^2+(0 ·…2025
• Calculate the standard Gibbs energy (Δ_r G^°) of the following reaction at 25 °C: 3 + 2 Au(s)+Ca^2+(1 M) → Au^3+(1 M)+Ca(s)…2025
• Calculate the standard Gibbs energy (Δ_r G^°) of the following reaction at 25 °C: 3 + 2 Au( s)+Ca^2+(1 M) → Au^3+(1 M)+Ca( s);…2025
• Write the cell reaction and calculate the e.m.f. of the following cell at 298 K: ( 3 + 2 = 5 ) Sn(s)|Sn^2+(0.004 M)||H^+(0.02 M)|…2025
• (i) Calculate the emf of the following cell at 25°C: Zn(s)|Zn^2+(0.1 M)||H^+(0.01 M)| H_2( g) (1 bar), Pt(s) [ Given: E_Zn^2+ /…2025
• The molar ionic conductivities of Ca^2+ and Cl^- are 119.0 and 76.3 S cm^2 mol^-1 respectively. The value of limiting molar…2024
• The product of oxidation of SO_3^2- with MnO_4^- in acidic medium is:2024
• The molar ionic conductivities of Al^3+ and SO_4^2- are 189 S cm^2 mol^-1 and 160 S cm^2 mol^-1 respectively. The value of…2024
• The equilibrium Cr_2 O_7^2- ⇌ 2 CrO_4^2-:2024
• The molar ionic conductivities of Mg^2+ and SO_4^2- are 106.0 S cm^2 mol^-1 and 160.0 S cm^2 mol^-1 respectively. The value of…2024
• Which of the following cell was used in Apollo space programme?2024
• The unit of cell constant is:2024
• During electrolysis of aqueous CuCl_22024
• Which of the following cell is used in inverter?2024
• During electrolysis of aqueous solution of NaCl:2024
• Which of the following cells is used in hearing aids?2024
• Dilution affects both conductivity as well as molar conductivity. Effect of dilution on both is as follows:2024
• During the electrolysis of aqueous NaCl, the cathodic reaction is:2024
• Which of the following is a secondary cell?2024
• Assertion: For a Daniell cell, Zn / Zn^2+(1 M) ∥ Cu^2+(1 M) / Cu with E^° cell =1.1 V, if the external opposing potential is more…2024
• Define the following terms: Faraday's second law of electrolysis Corrosion2024
• Calculate the potential of Iron electrode in which the concentration of Fe^2+ ion is 0.01 M. ( E^0 Fe^2+ / Fe=-0.45 V at 298 K )…2024
• State: Kohlrausch law of independent migration of ions. Faraday's first law of electrolysis.2024
• Resistance of a conductivity cell filled with 0.2 mol L^-1 KCl solution is 200 Ω. If the resistance of the same cell when filled…2024
• Define the following terms: 1 × 2 Limiting molar conductivity (Λ^° m) Fuel cell2024
• Complete the following ionic equations: 2 MnO_4^-+5 SO_3^2-+6 H^+ → Cr_2 O_7^2-+14 H^++6 Fe^2+ →2024
• When a certain conductivity cell was filled with 0.05 M KCl solution, it has a resistance of 100 ohm at 25°C. When the same cell…2024
• Calculate emf of the following cell at 25 °C: Sn / Sn^2+(0.001 M) ∥ H^+(0.01 M)|H_2( g)(1 bar)| Pt_(s) Given: E^°(Sn^2+ /…2024
• The conductivity of 0 · 2 M solution of KCl is 2 · 48 × 10^-2 S cm^-1. Calculate its molar conductivity and degree of…2024
• Calculate emf of the following cell: Zn(s)|Zn^2+(0 · 1 M)||Sn^2+(0 · 001 M)| Sn(s) Given: E_Zn^2+ / Zn^0=-0 · 76 V, E_Sn^2+ /…2024
• Calculate the emf of the following cell: 3 Ni(s)+2 Ag^+(0.01 M) → Ni^2+(0.1 M)+2 Ag(s) Given that E_cell^°=1.05 V, log 10=12024
• Batteries and fuel cells are very useful forms of galvanic cell. Any battery or cell that we use as a source of electrical energy…2024
• In a galvanic cell, chemical energy of a redox reaction is converted into electrical energy, whereas in an electrolytic cell the…2024
• (i) Calculate emf of the following cell at 25°C: Zn( s)|Zn^2+(0 · 001 M)||Cd^2+(0 · 1 M)| Cd( s) Given: E_Zn^2+ / Zn^o=-0.76 V,…2024
• (i) The resistance of 0.05 M CH_3 COOH solution is found to be 100 ohm. If the cell constant is 0.0354 cm^-1, calculate the molar…2024
• Consider the following standard electrode potential values: Fe^3+_(aq)+e^- → Fe^2+_(aq) E^°=+0.77 V MnO_4^-_(aq)+8 H^++5 e^- →…2023
• Consider the following standard electrode potential values: Sn^2+_(aq)+2 e^- → Sn_(s) E^°=-0.14 V Fe^3+_(aq)+e^- → Fe^2+_(aq)…2023
• The correct cell to represent the following reaction is: Zn+2 Ag^+ → Zn^2++2 Ag2023
• Ag^+(aq)+e^- → Ag(s) E^°=+0.80 V Fe^2+(aq)+2 e^- → Fe(s) E^°=-0.44 V Find the E_cell^° for: Fe(s)+2 Ag^+(aq) → Fe^2+(aq)+2 Ag(s)2023
• A voltaic cell is made by connecting two half cells represented by half equations below: Sn^2+_(aq)+2 e^- → Sn_(s) E^°=-0.14 V…2023
• Four half reactions I to IV are shown below: I. 2 Cl l^- → Cl_2+2 e^- II. 4 OH^- → O_2+2 H_2 O+2 e^- III. Na^++e^- → Na IV. 2…2023
• Δ G and E_cell^° for a spontaneous reaction will be:2023
• The unit of molar conductivity is2023
• Which of the following solutions of KC l will have the highest value of molar conductivity?2023
• Which of the following relations is incorrect?2023
• Corrosion of iron is:2023
• The number of faradays passed through a solution of CuSO_4 to produce 1 mol of Cu and O_2 will be:2023
• How many Faradays are required to reduce 1 mol of MnO_4^- to Mn^2+?2023
• Which of the following cell was used in Apollo space programme?2023
• Assertion (A): Λ_m for weak electrolytes shows a sharp increase when the electrolytic solution is diluted. Reason (R): For weak…2023
• Assertion: Electrolysis of aqueous solution of NaCl gives chlorine gas at anode instead of oxygen gas. Reason (R): Formation of…2023
• Assertion: Molar conductivity decreases with increase in concentration. Reason (R): When concentration approaches zero, the molar…2023
• Assertion (A): Λ_m for weak electrolytes shows a sharp decrease when the electrolytic solution is diluted. Reason (R): For weak…2023
• Assertion: Conductivity decreases with decrease in concentration of electrolyte. Reason (R): Number of ions per unit volume that…2023
• Assertion (A): Limiting molar conductivity (Λ_m^°) is obtained by the extrapolation of the Λ_m versus C^1 / 2 curve of strong…2023
• Assertion: E_Cu^° 2+/ Cu is positive (+0.34 V). Reason (R): Copper has high Δ_a H^° and low Δ_hyd H^°.2023asked 2×
• Calculate Δ_r G^° for the cell reaction at 25°C: Zn|Zn^2+ ∥ Cd^2+| Cd Given that: E_Zn^2+ / Zn^°=-0.76 V, E_Cd^2+ / Cd^°=0.40 V;…2023
• On diluting two electrolytes'A'and'B', the Λ_m of'A'increases 25 times while that of'B'increases by 1.5 times. Which of the two…2023
• Give reasons: 2 × 1 (i) Mercury cell delivers a constant potential during its life time. (ii) In the experimental determination…2023
• Name the cell which: was used in Apollo Space programme. is used in automobiles and inverters. is suitable for hearing aids and…2023
• Define fuel cell and write its two advantages. OR Using E^° values of X and Y given below, predict which is better for coating…2023
• Complete the following equations: 2 MnO_4^-+5 NO_2^-+6 H^+ → Cr_2 O_7^2-+14 H^++6 e^- →2023
• (i) What should be the signs (positive/negative) for E^°_Cell and Δ G^° for a spontaneous redox reaction occurring under standard…2023
• Rahul set-up an experiment to find resistance of aqueous KCl solution for different concentrations at 298 K using a conductivity…2023
• (i) State Kohlrausch's law of independent migration of ions. Write an expression for the limiting molar conductivity of acetic…2023
• (i) Calculate the emf of the following cell at 298 K: Al( s)|Al^3+(0.001 M) ∥ Ni^2+(0.1 M)| Ni( s); [ Given: E_Al^°^3+ / Al=-1.66…2023
• Conductivity of 2 × 10^-3 M methanoic acid is 8 × 10^-5 S cm^-1. Calculate its molar conductivity and degree of dissociation if…2023
• Calculate the emf of the following cell at 25°C: Zn( s)|Zn^2+(0 · 1 M) ∥ H^+(0 · 01 M)| H_2( g)(1 bar ), Pt(s) [Given: E_Zn^2+ /…2023
• (i) Why on dilution the Λ_m of CH_3 COOH increases very fast, while that of CH_3 COONa increases gradually? (ii) What happens if…2022
• The resistance and conductivity of a conductivity cell containing 0.001 M KCl solution at 298 K are 1200 Ω and 1.5 × 10^-4 S…2022
• In a plot of Λ_m against the square root of concentration (C^1 / 2) for strong and weak electrolyte, the value of limiting molar…2022
• In the plot of molar conductivity (Λ_m) Vs. square root of concentration (√C), following curves are obtained for two electrolytes…2022
• Define molar conductivity for the solution of an electrolyte. How does it vary with concentration?2022
• Out of the following pairs, predict with reason which will allow greater conduction of electricity: (i) 1 M CH_3 COOH solution or…2022
• Define conductivity for the solution of an electrolyte. Why does the conductivity of a solution decrease with dilution?2022
• Write the Nernst equation for the following cell reaction: Zn( s)+Cu^2+(aq) → Zn^2+(aq)+Cu( s) How will the E_cell be affected…2022
• The conductivity of 0.001M acetic acid is 7.8 × 10^-5 S cm^-1. Calculate its degree of dissociation if Λ^° m for acetic acid is…2022
• (i) State Kohlrausch's law of independent migration of ions. (ii) Calculate the degree of dissociation ( α ) of CH_3 COOH if Λ_m…2022
• Calculate Δ_r G^° and log Kc for the following cell: Ni( s)+2 Ag^+(aq) → Ni^2+(aq)+2 Ag( s); Given that E^° cell =1.05 V,…2022
• Calculate the emf of the following cell: Zn( s)|Zn^2+(0 · 01 M) ∥(0 · 001 M) Ag^+| Ag( s) Given: E_Zn^2+ / Zn^ =-0.76 V and…2022
• The standard Gibbs energy (Δ r G^°) for the following cell reaction is -300 kJ mol^-1: Zn( s)+2 Ag^+(aq) → Zn^2+(aq)+2 Ag( s)…2022
• Write the Nernst equation and calculate the emf of the following cell at 298 K: Zn|Zn^2+(0 · 1 M) ∥ Cd^2+(0 · 01)| Cd Given:…2022
• Write the Nernst equation and calculate the emf of the following cell at 298 K: 3 Zn|Zn^2+(0 · 001 M) ∥ H^+(0 · 01 M)| H_2( g)(1…2022
• Write the Nernst equation and calculate emf of the following cell at 298 K: Cr|Cr^3+(0 · 1 M) ∥ Fe^2+(0 · 01 M)| Fe Given:…2022
• Read the passage given below and answer the questions that follow: Oxidation-reduction reactions are commonly known as redox…2022

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