Unlike dry cell, the mercury cell has a constant cell potential throughout its useful life. Why?
Electrolyte is not consumed in the cell process of mercury cell hence it will deliver the current at constant potential throughout its life.
The conductivity of 0.20 M solution of KCl at 298 K is 0.0248 S cm-1. Calculate its molar conductivity.
How much charge is required for the following reductions:
(i) 1 mol of Al3+ to Al?
(ii) 1 mol of Cu2+ to Cu ?
(iii) 1 mol of Mn04- to Mn2+?
The positive value of the standard electrode potential of Cu+2/Cu indicates that
(a) this redox couple is a stronger reduction agent than the H/H2 couple
(b) this redox couple is a stronger oxidizing agent than H+/H2
(c) Cu can displace H2 from acid
(d) Cu cannot displace H2 from acid
Calculate the potential of hydrogen electrode in contact with a solution whose pH is 10.
Three electrolytic cells A, B, C containing solutions of ZnS04, AgNO3 and CuS04, respectively are connected in series. A steady current of 1.5 amperes was passed through them until 45 g of silver deposited at the cathode of call B. How long did the current flow? What mass of copper and zinc were deposited?
E °en = 1.1 V for Daniell cell. Which of the following expressions are correct description of state of equilibrium in this cell?
What will happen during the electrolysis of aqueous solution of CuSO4 in the presence of Cu electrodes?
(a) Copper will deposit at cathode.
(b) Copper will dissolve at anode.
(c) Oxygen will be released at anode.
(d) Copper will deposit at anode.
Assertion (A): E , increases with increase in concentration of Ag+ ions.
Ag / Ag+
Reason (R): E + has a positive value.
Ag /Ag
Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration.
Consultthe table of standard electrode potentials and suggest three substances that can oxidise ferrous ions under suitable conditions.
Consider the figure given below and answer the questions (i) to (vi) that follow.
(i) Redraw the diagram to show the direction of electron flow.
(ii) Is silver plate anode or cathode?
(iii)What will happen if salt bridge is removed?
(iv)When will the cell stop functioning?
(v)How will concentration of Zn+2 cell functions?
(vi)How will the concentration of Zn+2 ions and Ag+ ions be affected after the cell becomes ‘dead'?
In the button cells widely used in watches and other devices the following reaction takes place:
The cell in which the following reaction occurs: 2Fe3+ (aq) + 2I– (aq) —> 2Fe2+ (aq) +I2 (s) has E °cell=0.236 V at 298 K. Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.
Write the Nemst equation for the cell reaction in the Daniell cell. How will the Ecell be affected when concentration of Zn2+ ions is increased?
Which reference electrode is used to measure the electrode potential of other electrodes?
Calculate the emf of the cell in which the following reaction takes place:
Ni(s)+2Ag+ (0.002 M) -> Ni2+ (0.160 M)+2Ag(s) Given that E(-)(cell) = 1.05 V .
In an aqueous solution, how does specific conductivity of electrolytes change with addition of water?
Given the standard electrode potentials, K+/K=-2. 93 V, Ag+/Ag = 0.80 V, Hg2+/Hg =0.79V, Mg2+/Mg=-2.37V, Cr3+/Cr=0.74V.
Arrange these metals in their increasing order of reducing power.
Use the data given in Q. 8 and find out which of the following is the strongest oxidizing agent.
How much electricity in terms of Faraday is required to produce .
(i) 20.0 g of Ca from molten CaCl2?
(ii) 40.0 g of Al from molten Al203?
The quantity of charge required to obtain one mole of aluminium from
Al2O3 is (a) IF (b) 6F (c) 3F (d) 2F
Write the cell reaction of a lead storage battery when it is discharged. How does the density of the electrolyte change when the battery is discharged?
Solutions of two electrolytes 'A' and 'B' are diluted. The Am of 'B' increases 1.5 times while that of A increases 25 times. Which of the two is a strong electrolyte? Justify your answer.
In the electrolysis of aqueous sodium chloride solution, which of the half-cell reaction will occur at anode?
Assertion (A): Electrolysis of NaCl solution gives chlorine at anode instead of 02.
Reason (R): Formation of oxygen at anode requires overvoltage.
Assertion (A): For measuring resistance of an ionic solution an AC source is used.
Reason (R): Concentration of ionic solution will change if DC source is used.
What is the relationship between Gibbs free energy of the cell reaction in a galvanic cell and the emf of the cell? When will the maximum work be obtained from a galvanic cell?
A solution of Ni(N03)2 is electrolyzed between platinum electrodes using a current of 5 amperes for 20 minutes. What mass of Ni is deposited at the cathode?
Conductivity of an electrolytic solution depends on
(b) concentration of electrolyte
(d) distance between the electrodes
Unlike dry cell, the mercury cell has a constant cell potential throughout its useful life. Why?
Assertion (A): Ecell should have a positive value for the cell to function. Reason (R). Ecadlode Eanode
Depict the galvanic cell in which the reaction
Zn(s) + 2Ag+(aq) —-> 7M2+(aq) + 2Ag (s) takes place. Further show:
(i) Which of the electrode is negatively charged?
(ii) The carriers of the current in the cell.
(iii) Individual reaction at each electrode.
What will happen during the electrolysis of aqueous solution of CuSO4 by using platinum electrodes?
(a) Copper will deposit at cathode.
(b) Copper will deposit at anode.
(c) Oxygen will be released at anode.
(d) Copper will dissolve at anode.
Aqueous copper sulphate solution and aqueous silver nitrate solution are electrolysed by 1 ampere current for 10 minutes in separate electrolytic cells. Will the mass of copper and silver deposited on the cathode be same or different? Explain your answer.
mean? Zn /Zn
