Electrochemistry Questions and Answers
Physical Chemistry
ElectrochemistryFor a electrolyte A By which of the following is correct for kohlroush law Aq x Aa Av Y A Br X B Am X Am AY y Am gr B Aeq xea Ay Bx X y Aq X Am Ax y Am By
Physical Chemistry
Electrochemistry2 For given half cell Al 3e Al on increasing Al the electrode potential 1 Increases 2 Decreases 3 No change he Istem n2 aid of 4 First increases then decreases
Physical Chemistry
ElectrochemistryConsider the following electrochemical cell a Write a balanced net ionic equation for the spontaneous reaction that take place in the cell b Calculte the standard cell potential E for the cell reaction c If the cell emf is 1 6 V what is the concentration of Zn d How will the cell potential be affected if KI is added to Ag half cell Zn E AD Ag 0 8 V E12 0 76 V Zn NO3 2 Salt Bridge Ag 0 1 M AgNO
Physical Chemistry
ElectrochemistryGiven Sn Sn 2e E 0 66 V Fe Fe 2e E 0 33 V Most strong oxidising agent will be 2 Sn 4 Fe 1 Sn 2 3 Fe ALLEN 64 framan Sn Sn 2c E 0 66 V Fe Fe 2e E 0 33 STTUR Ses van fasech Brit 1 Sn 3 Fe 2 Sn 4 Fe
Physical Chemistry
Electrochemistry73 Given that Ni Ni 0 25 V Cu Cu 0 34 V Ag Ag 0 80 V Zn Zn 0 76 V Which of the following reactions under standard condition will not take place in the specified direction 1 Ni Cu Nis Cu aq 2 2Ag Cu s 2Ag s Cu2 2 3 Zn Cu ALLEN 73 Cu s fe Ni Ni 0 25 V Cu Cu 0 34 V Ag Ag 0 80 V Zn Zn 0 76V f fuff sta 1 N4 Cu s 2 2Ag Cu aq 3 Zn Cu aq Nis Cu 2Ag Cut Cu s 11 aq Zn
Physical Chemistry
Electrochemistry28 If the density of copper is 8 94 g cm the number of Faradays required to plate an area 10cm x 10cm of thickness of 10 2 cm using CuSO solution as electrolyte is 2 0 28 F 4 0 5 F 1 0 1 F 3 0 4 F
Physical Chemistry
Electrochemistry3 3 Zn Cu 4 2H aq Zn s H2 g If the specific conductance and conductance of a 74 solution are same then its cell constant is equal to 2 0 3 10 4 100 Zn Cu s aq 2 3 Zn Cu Zn Cu s aq H2 g 2 aq 4 2H Zn s aq fastfera un fafing art fra andre fontes 1 1 2 0 Zn aq 3 10 4 100
Physical Chemistry
ElectrochemistryIn the cell reaction H 2 atm H H IH p atm for spontaneous cell reaction the value of p should 1 Less than 2 atm 2 Greater than 2 atm 3 Equal to 2 atm AY Any value of pressure
Physical Chemistry
Electrochemistry2 A current of 0 965 ampere is passed through 500 ml of 0 2 M solution of ZnSO4 for 10 minutes The molarity of Zn after deposition of zinc is 1 0 1 M 2 0 5 M 3 0 8 M 18 4 0 194 M
Physical Chemistry
Electrochemistry63 Electrode potential data are given below S A 3 2 Fe aq eFe aq Fe E 0 77 V Alaq 3e Al s E 1 66 V Br2 aq 2e 2Br aq E 1 66 V Based on the above data which statement s incorrect 8 1 Fe2 is stronger reducing agent than Br 2 Fe2 is stronger oxidising agent than Al 3 Al is stronger reducing agent than Fe2 2 4 Bris stronger reducing agent than Al 2
Physical Chemistry
ElectrochemistryConsider two strong electrolytes NaCl and KCI The molar conductance Am and concentration C for strong electrolytes can be related as A A B C What can be said about the values of A and B for KCI and NaCl Both have same value of A as well as B Both have same value of A but different value of B Both have different value of A but same value of B Both have different value of A as well as different value of B
Physical Chemistry
ElectrochemistryAn acid base indicator has K 3 0x10 The acid form of the indicator is red and the basic form is blue Then which of the following statement s is are correct Take log3 0 48 pH is 4 04 when indicator is 75 red pH is 5 00 when indicator is 75 blue pH is 5 00 when indicator is 75 red pH is 4 05 when indicator is 75 blue
Physical Chemistry
Electrochemistry9 An electrolytic cell is composed of Cu and Zn current of 9 65 A is drawn from a cell for 1 hou Then the loss in mass at anode and gain in mas at cathode respectively could be 1 11 77 g 11 43 g 3 22 86 g 23 54 g 2 11 77 g 10 g 4 23 54 a 2386
Physical Chemistry
ElectrochemistryHow long must a 50 0 A current be passed through an electrolytic cell fo refining copper to produce 3 00 mole of copper Options 1 O 1 50 hrs 2 O 1 61 hrs 3 O 2 50 hrs 4 O3 21 hrs
Physical Chemistry
Electrochemistry5 Which of the following is not correct 1 Molar conductance of a solution increases with dilution 2 Equivalent conductance increases with dilution 3 Specific dilution conductance increases with 4 At infinite dilution each ion cation or anion plays a definite role towards electrical conductance
Physical Chemistry
ElectrochemistryHydrazine can be used in fuel cell N H4 aq O2 g N2 g 2H O 0 If AG for this reaction is 600 kJ what will be the E for the cell 1 1 25 V 3 1 57 V 2 1 50 V 4 1 75 V
Physical Chemistry
ElectrochemistryEquivalent conductivity of BaCl2 H SO4 and HCl are x x2 and x cm eq at infinite dilution If conductivity of saturated BaSO solution x 5 cm then Ksp of BaSO4 is A B D 500x X X2 2X3 105x2 X X 2X3 2 5 x 105x X X2 X3 0 25x X X2 X3
Physical Chemistry
Electrochemistryaction If the standard electrode potential of Cu Cu electrode is 0 34 V what is the electrode potential of 0 1 M 2 Equilibrium constant 4 All of these 8 concentration of Cu 1 3 99 V 2 0 3105 V 3 0 222 V If Cu Cu electrode is diluted 100 times then the change in emf is 4 0 176 V
Physical Chemistry
ElectrochemistryThe molar conductivities of ADAC and AC are given at 25 C To calculate ADAC molar conductivity of other electrolyte required i O ANaci O ANaOH O A 0
Physical Chemistry
Electrochemistry18 The specific conductivity of N 10 KCI solution at 20 C is 0 0212 ohm 1 cm 1 and the resistance of the cell containing this solution at 20 C is 55 ohm The cell constant is ON 2 1 166 cm 1 4 3 324 cm 10 1 4 616 cm 1 3 2 173 cm 1
Physical Chemistry
ElectrochemistryWhen two half cell of electrode potential of Ea and Eb are combined to form a cell of electrode potential E then If na n and n are no of electron exchange in 1st 2nd and combined half cell A E Eb Ea B E a En En n En E n 12 C E n D E Ea Eb
Physical Chemistry
ElectrochemistryGiven that 1312 8 E 3 m Fe 8 2 m so 68 ohm 1 cm mol and 80 ohm cm mol 1 ea Fe2 SO4 3 eq What will be e 148 ohm cm eq 880 ohm cm eq 364 ohm 1 cm eq 130 ohm cm eq
Physical Chemistry
Electrochemistry45 If the colour changes in an acid base indicator pKindicator 7 2 are as given below which of the following is correct HIn aq A B C D Yellow H aq In aq Pink In a strong alkaline solution pink colour will be observed In a strong acidic solution pink colour is observed In a strong alkaline solution yellow colour is observed At pH 5 5 In is more than HIn
Physical Chemistry
Electrochemistry5 Saturated solution of KNO3 is used to make salt bridge because 1 Velocity of K is greater than that of NO 2 Velocity of NO is greater than that of K 3 Velocity of K and NO3 are nearly same 4 KNO3 is highly soluble in water
Physical Chemistry
Electrochemistry8 The standard reduction potential values of three metals X Y and Z are 0 52 3 303 and 1 18V respectively The order of reducing power of the corresponding metal is 1 Y Z X 2 X Y Z 3 Z Y X 4 Z X Y
Physical Chemistry
Electrochemistry26 Calculate AG for the galvanic cell 2Cr s 3Cd aq 2Cr 3 aq 3Cd s Er 3 Cr 0 74 V EC Cd 0 40 V Senco 1 196 86 kJ mol 3 65 62 kJ mol 2 98 43 kJ mol 4 164 05 kJ mol
Physical Chemistry
ElectrochemistryIn electrochemistry chapter under the topic electrolysis w ith same type of electrode sir said that on electrolysis of FeSO4 we will get Fe at cathode and Fe at anode But reduction potential of Fe is smaller than H then wh y this will happen at cathode
Physical Chemistry
ElectrochemistryPre Medical Chemistry Given below are the half cell reactions Mn 2e Mn E 1 18 V 2 Mn e Mn E 1 51 V The Eo for 3Mn Mn 2Mn3 will be 1 0 33 V the reaction will not occur 2 0 33 V the reaction will occur 3 2 69 V the reaction will not occur 4 2 69 V the reaction will occur ut Explain full question ow Mainly explain how we get n 2 for resultant reaction
Physical Chemistry
ElectrochemistryConsider the following statements for lead storage battery a It consists of a grid of lead packed with PbO2 as anode and a lead cathode b 38 solution of H SO4 is used as an electrolyte c It is commonly used in automobiles and invertors Which of the above statements are correct O a and c Ob and c O a and b
Physical Chemistry
ElectrochemistryWhen Eext 1 1 volt is applied in Daniel cell having electrodes of zinc and copper dipping in one molar solutions of their respective salts then O Electrons flow from Cu to Zn O Electrons flow from Zn to Cu O Zn dissolves at anode and Cu deposits at cathode O No flow of electrons or current
Physical Chemistry
Electrochemistry1 Q 53 The solubility of Co Fe CN 6 in water at 25 C from the following data Conductivity of saturated solution of Co Fe CN 6 2 06 x 106 ohm cm and that of water 4 1 x 107 ohm cm The ionic molar conductivities of Co and Fe CN are 86 and 444 ohm cm mol respectively is 2 x 10 mol
Physical Chemistry
ElectrochemistryLimiting molar conductivity of CH COOH ie Am CH3COOH is equal to O Am HCB Am NaC1 Am CH COONa O Am HCB Am CH COONS Am N CI
Physical Chemistry
ElectrochemistryAn aquous solution containing IM NISO and IMS O is electrolysed using palladium electrode at 25 C Ni 2 Ni E 0 25V 21 2e H E 0 00V O 4H 4e 2H O E 1 23V Pd 2 Pd E 0 92V S O 2 2SO E 2V pH of solution is 7 Select the correct statement s on the basis of given information Ignore over voltage and neglect variation with cocentration A Reaction at anode is Pd Pd 2 C Reaction at cathode is Ni 2 Ni B Reaction at anode is 2H O O 4H 4e D Reaction at cathode is 2H 2 H
Physical Chemistry
ElectrochemistryA For the reaction Fe 2 aq Ag aq Ag s Fe aq Predict which change will decrease the cell voltage 1 Increase the amount of Ag 3 Increase the concentration of Fe 3 2 Decrease the concentration of A 4 Both 2 3
Physical Chemistry
ElectrochemistryQ 53 The e m f of cell Zn ZnSO4 CuSO4 Cu at 25 C is 0 03 V and the temperature coefficient of e m f is 1 4 x 10 V per degree The heat of reaction for the change taking place inside the cell is kJ mol
Physical Chemistry
ElectrochemistryQ 59 Dipole moment of HX is 2 59 x 10 30 coulomb metre Bond length of HX is 1 39 bns The ionic character of molecule is
Physical Chemistry
ElectrochemistryPurification of chromium can be achieved by electrorefining chromium from an impure chromium anode onto a pure chromium cathode in an electrolytic cell How many hours will it take to plate 13 0 kg of chromium onto the cathode if the current passed through the cell is held constant at 41 0 A Assume the chromium in the electrolytic solution is present as Cr
Physical Chemistry
ElectrochemistryThe reduction potential of H electrode in a solution of 0 1 M H aq is PH 1 atm 0 0591 V 0 591 V nr min 0 0591 V
Physical Chemistry
ElectrochemistryCalculate the reduction potential of a half cell having reaction Ag S s 2e 2Ag S S aq in a solution buffered at p 3 and which is also saturated with 0 1M H S aq Given K Ag S 10 Kal Ka 10 E As Ag 2 303 RT F 0 06 A 0 19V B 0 19 C 1 18V D 1 18 V 0 8V
Physical Chemistry
ElectrochemistryAmount of electricity required to reduce 0 5 mole of A1 ions to Al atoms is 3 F 2 F hr 0 5 F
Physical Chemistry
ElectrochemistryWhen electrochemical cell is changed into electrolytic cell then why sign of cathode positive only Has ncert mentioned it wrobg in the diagram pls tell corre ct explanation teacher properly c Cathode ve Zn ZnSO4 Eext 1 1 W e CuSO4 Current Anode ve Cu ii No cha reacti When Eext 1 i Electrons e from Cuper and curre from Zn t ii Zinc is de at the zind electrode a copper diss copper elec
Physical Chemistry
ElectrochemistryHow much amount of water can be decomposed through electrolysis by passing 2 F charge 2 5 mol of water 3 mol of water 3 5 mol of water 1 mol of water
Physical Chemistry
ElectrochemistryCalculate the volume of O liberated at STP by 81 passing 5A current for 193 sec through acidified water 1 56 mL 3 158 mL 2 112 mL 4 965 mL PRIR 2912 1 5e 3 15 0500
Physical Chemistry
Electrochemistry2 F electricity was passed through molten FeO Weight of iron metal Atomic wt 56 deposited at cathode in g is 112 84 56 28
Physical Chemistry
ElectrochemistrySalt bridge A concentration cell similar to the one shown is composed of twa Ph electrodes and solmons of different Pb2 concentrations The left compartment contains 1 25 M Ph and t compartment contains 2 26 162 Ph Calculate the cell potential for this reaction at 298 K volly
Physical Chemistry
ElectrochemistryTHE CORRECT ANSWER 9 A Daniel Cell may be represented as Zn s Cu2 aq Zn2 aq Cu s If AG 293 formation 0 for Zn s and Cu s 35 14 Kcal mol for Zn aq and 15 66 Kcal mol for Cu 2 aq calculate the E for the cell and equilibrium constant of the reaction under standard condition
Physical Chemistry
ElectrochemistryIn a galvanic cell Cu is reacting with nitric acid to produce NO or NO At what NO3 tendency of formation of NO NO is same E Cu Cu E 0 34V NO NO H E 0 79V 0 96V NO NO H Assume pressure of all the gases are taken as unity P NO PN NO
Physical Chemistry
ElectrochemistryM The equivalent conductance of 10 Given A HA 80 ohm cm eq 2 5 x 10 4 3 5 10 3 6 5 x 10 4 5 5 10 5 solution of a weak monobasic acid HA is 4 ohm cm eq The dissociation constant of the acid will be
Physical Chemistry
Electrochemistry71 Study the given figure and answer the question that follow t A OF i Give the names of the electrodes A and B a A Cathode B Anode b A Anode B Cathode c A Anode B Anode d A Cathode B Cathode ii Which electrode is the oxidising electrode a A b B c Both a and b
Physical Chemistry
Electrochemistry5 8 S cm mol During the electrolysis of molten sodium chloride the time required to produce 0 10 mol of chlorine gas us a current of 3 amperes is 1 220 minutes 44 110 minutes 2 330 minutes 3 55 minutes 900