electrochemistry
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Multiple Choice Questions on Electrochemistry, Electrochemical cellsTRANSCRIPT
Electrochemistry
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1Which of the following substances Na, Hg, S, Pt and graphite can be used as electrodes in electrolytic cells having aqueous solution?( )Na, Pt and graphite
( )Na and Hg
( )Pt and graphite
( )Na and S
Single Answer
2When quantity of electricity passed is one faraday then the mass deposited at the electrode is equal to( )One gm.atomic weight
( )One gm.Equavalent weight
( )Electrochemical equivalent
( )None of the above
Single Answer
3If a salt bridge is removed between the two half cells, the voltage ( )Drops to zero
( )Does not change
( )Increases gradually
( )Increases rapidly
Single Answer
4The reference calomel electrode is made from which of the following?( )ZnCl2
( )CuSO4
( )Hg2Cl2
( )HgCl2
Single Answer
5When electricity is passed through molten Al2O3+Na3AlF6 and 13.5gms of Al are deposited, the number of faradaymust be( )0.5
( )1.0
( )1.5
( )2.0
Single Answer
6An electrode( )Forms complex ions in solution
( )Gives ions only when electricity is passed
( )Possesses ions even in solid state
( )Gives ions only when dissolved in water
Single Answer
7A cell constant is generally found by measuring the conductivity of aqueous solution of( )BaCl2
( )KCl
( )NaCl
( )MgCl2
Single Answer
8A solution of sodium sulphate was electrolysed using some inert electrodes. The products at the electrodes are( )O2,H2
( )O2,Na
( )O2,SO2
( )O2,S2O8^2-
Single Answer
9A current of 9.65A flowing for 10 minutes deposits 3.0 g of the metal which is monovalent. The atomic mass of the metal is( )10
( )50
( )30
( )96.5
Single Answer
10A certain current liberates 0.5 g of hydrogen in 2 h. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution?( )12.7g
( )15.9g
( )31.8g
( )63.5g
Single Answer
11Out of Cu, Ag, Fe and Zn the metal which can displace all others from their salt solutions is( )Ag
( )Cu
( )Zn
( )Fe
Single Answer
12The conductivity of strong electrolyte( )Increases on dilution slightly
( )Does not change on dilution
( )Decreases on dilution
( )Depends on density of electrolyte itself
Single Answer
13The amount of electricity that can deposit 108 g of silver from silver nitrate solution is( )1 ampere
( )1 coulumb
( )1 faraday
( )2 amperes
Single Answer
14In a galvanic cell( )Chemical energy is converted into electricity
( )Chemical energy is converted into heat
( )Electrical energy in converted into heat
( )Electrical energy is converted into chemical energy
Single Answer
15When electricity is passed through molten electrolyte consisting of alumina and cryolite, 13.5 g of Al are deposited. The number of faradays of electricity passed must be( )2.0
( )1.5
( )1.0
( )0.5
Single Answer
16Which of the following is a strong electrolyte?( )Ca(NO3)2
( )HCN
( )CH3COOH
( )NH4OH
Single Answer
17Pure water does not conduct electricity because it( )Has low boiling point
( )Is almost unionized
( )Is neutral
( )Is readily decomposed
Single Answer
1896500 C of electricity liberates from CuSO4 solution( )63.5 g of Cu
( )31.75 g of Cu
( )96500 g of Cu
( )100 g of Cu
Single Answer
19Which of the following is the use of electrolysis?( )Electrorefining
( )Electroplating
( )Both a and b
( )None of the above
Single Answer
20In a solution of CuSO4 how much time will be required to precipitate 2g Cu by 0.5 ampere current?( )12157.48 sec
( )102 sec
( )510 sec
( )642 sec
Single Answer
212.5 faraday of electricity is passed through solution of CuSO4. The number of gram equivalents of copper deposited on the cathode would be( )1
( )2
( )2.5
( )1.25
Single Answer
22Reaction takes place at anode is( )Ionization
( )Reduction
( )Oxidation
( )Hydrolysis
Single Answer
2396500 C electricity is passed through CuSO4. The amount of copper precipitated is( )0.25 mole
( )0.5 mole
( )1.0 mole
( )2.0 mole
Single Answer
24The art of electroplating was given by( )Faraday
( )Edison
( )Thomas Gradam
( )Brugan
Single Answer
25The number of coulumbs required for the deposition of 107.870 g of silver is( )96500
( )48250
( )193000
( )10000
Single Answer
26What will be the weight of deposited silver on passing 965 coulumbs of electricity in solution of AgNO3?( )1.08 g
( )2.16 g
( )0.54 g
( )0.27 g
Single Answer
27Pick out the wrong statement. In electrochemical cell( )Electrons are released at anode
( )Cathode is regarded as negative electrode
( )Chemical energy is converted into electrical energy
( )Salt bridge maintains the electrical neutrality of the solution
Single Answer
28Prevention of corrosion of iron by Zn coating is called( )Galvanization
( )Cathodic protection
( )Electrolysis
( )Photoelectrolysis
Single Answer
29The specific conductance of a 0.1 N KCl solution at 23 degree calsius is 0.012 /ohm.cm. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be( )0.14/cm
( )0.66/cm
( )0.918/cm
( )1.12/cm
Single Answer
30The substance having highest conductivity at room temperature among the following is( )0.1 N HCl
( )0.1 N NaCl
( )Graphite
( )Glass
Single Answer
31Best way to prevent rusting of iron is by( )Making iron cathode
( )Putting it in saline water
( )Both of these
( )None of these
Single Answer
32The specific conductance of 0.1 M NaCl solution is 1.06x10^-2 /ohm.mol. Its molar conductance in ohm^-1.cm2.mol^-1 is( )1.06x10^2
( )1.06x10^3
( )1.06x10^4
( )53
Single Answer
33Calculate the amount of charge flowing in 2 minute in a wire of resistance 10 ohm when a potential difference of 20 V is applied( )120 C
( )240 C
( )20 C
( )4 C
Single Answer
34The equivalent conductivity of 0.1 M week acid is 100 times less than that at infinite dilution. The degree of dissolution is( )100
( )10
( )0.01
( )0.001
Single Answer
35The standard EMF of Daniel cell is 1.10 volt. The maximum electrical work obtained from Daniel cell is( )212.3 kJ
( )175.4 kJ
( )106.15 kJ
( )53.07 kJ
Single Answer
36Conductivity (unit: siemen S) is directly proportional to the area of the vessel and the concentration of the solutin in it and is inversly proportional to the length of vessel, then the unit of constant of proportionality is( )Sm/mol
( )Sm2/mol
( )S-2 m2 mol
( )S2m2/mol-2
Single Answer
37A smuggler could not carry gold by chemically depositing iron on the gold surface since( )Gold is denser
( )Iron rusts
( )Gold has higher reduction potential than iron
( )Gold has lower reduction potential than iron
Single Answer
38In electrolysis of NaCl when Pt electrode is taken then H2 is liberated at cathode while with Hg cathode it forms sodium amalgam( )Hg is more inert than Pt
( )More voltage is required to reduce H+ at Hg than at Pt
( )Na is dissolved in Hg while it does not dissolve in Pt
( )Conc. of H+ ions is larger when Pt electrode is taken
Single Answer
39Corrosion is basically( )Altered reaction in presence of H2O
( )Electrochemical phenomenon
( )Interaction
( )Union between two light metals and a heavy metal
Single Answer
40The unit of conductiviyt is( )Ohm/cm
( )Ohm.cm2
( )Ohm-1.cm
( )Ohm-1.cm-1
Single Answer
41When during electrolysis of a solution of AgNO3, 9650 coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be( )1.08 g
( )10.8 g
( )21.6 g
( )108 g
Single Answer
42Standard reduction electrode potential of three metals A, B and C are respectilvely +0.05V, -3.0 and -1.2 V. The reducing power of( )B>C>A
( )A>B>C
( )C>B>A
( )A>C>B
Single Answer
43Same amount of electric current is passed through solutions of AgNO3 and HCl. If 1.08 g of silver is obtained in the first case, the amount of hydrogen liberated as S.T.P in the second case is( )112 cm3
( )22400 cm3
( )224 cm3
( )1.008 g
Single Answer
44Time required to deposit one millimole of aluminium metal by the passage of 9.65 amperes through molten electrolyte containing aluminium ion is( )30 s
( )10 s
( )30,000 s
( )10,000 s
Single Answer
45Which of the following (IM) conducts more electricity?( )Sulphuric acid
( )Boric acid
( )Nitric acid
( )Phosphorus acid
Single Answer
46If the standard electrode potential of CU2+/Cu electrode is 0.34 V, what is the electrode potential of 0.01 M concentration of Cu2+? (T=298 K)( )0.399 V
( )0.281 V
( )0.222 V
( )0.176 V
Single Answer
47An electric current is passed through silver voltameter connected to a water voltmeter. The cathode of the silver voltameter is 0.108 g more at the end of the electrolysis. The volume of oxygen evolved at S.T.P is( )56 cm3
( )550 cm3
( )5.6 cm3
( )11.2 cm3
Single Answer
48An electric current is passed through silver nitrate solution using silver electrodes. 10.79 g of silver was found to be deposited on the cathode if the same amount of electricity is passed through the copper sulphate solution using copper electrodes, the weeight of the copper deposited on the cathode is( )6.4 g
( )2.3 g
( )12.8 g
( )3.2 g
Single Answer
49The standard e.m.f of a galvanic cell involving cell reaction with n=2 is found to be 0.295 V at 25 degree calcius. The equilibrium constant of the reaction would be( )1.0x10^10
( )2.0x10^11
( )4.0x10^12
( )1.0x10^2
Single Answer
50Fro spontanity of a cell, which is correct?( ) dG=0, dE=0
( ) dG=-ve, dE=0
( ) dG=+ve, dE=0
( ) dG=-ve
Single Answer
51Specific conductivity of a solution( )Increases with dilution
( )Decreases with dilution
( )Remains unchanged with dilution
( )Depends on mass of electrolyte
Single Answer
52In a Galvanic cell, the electrons flow from( )Anode to cathode through the solution
( )Cathode to anode through the solution
( )Anode to cathode through the external circuit
( )Cathode to anode through the external circuit
Single Answer
53In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to( )Generate heat
( )Remove absorbed oxygen from electrode surfaces
( )Produce high purity water
( )Create potential difference between two electrodes
Single Answer
54The limiting molar conductivities ^ for NaCl, KBr and KCl are 126, 52 and 150 Scm2 respectively. The ^ for NaBr is( )128 Scm2/mol
( )302 Scm2/mol
( )278 Scm2/mol
( )176 Scm2/mol
Single Answer
55When a non-spontaneous reaction takes place at the expense of electrical energy the process is called( )Electrolysis
( )Ionization
( )Neutralization
( )Electrical conduction
Single Answer
56Using inert electrodes like Pt or graphite the electrolysis of aqueous sodium chloride produces at cathode( )Cl2 gas
( )H2 gas
( )O2 gas
( )HCl gas
Single Answer
57In the presence of copper electrodes the electrolysis of aqueous CuSO4 produces at cathode( )H2 gas
( )O2 gas
( )SO2 gas
( )Cu metal
Single Answer
58The cathodic reaction in the electrolysis of dil.H2SO4 with Pt electrodes( )Reduction
( )Oxidation
( )Both oxidation and reduction
( )Neither oxidation nor reduction
Single Answer
59Which of the following statement about galvanic cell is true( )Anode is negatively charged
( )Reduction occurs at anode
( )Cathode is positively charged
( )Reduction occurs at cathode
Single Answer
60The electrode through which the electons enter the electrolytic solution is ( )Anode
( )Cathode
( )May be anode or cathode
( )None of these
Single Answer
61If the salt bridge is not used between two half cells, then the voltage( )Decrease rapidly
( )Decrease slwly
( )Does not change
( )Drops to zero
Single Answer
62When fused PbBr2 is electrolyzed( )Bromine appears at the cathode
( )Lead appears at the cathode
( )Lead appears at the anode
( )None of these
Single Answer
63When electric current is used t carry out non-spontaneous redox reaction, the process is called( )Hydrolysis
( )Electrolysis
( )Decomposition
( )Neutralization
Single Answer
64By using graphite electrode the electrolysis of aqueous solution of NaCl produces at anode( )H2 gas
( )Cl2 gas
( )NaOH
( )Na metal
Single Answer
65The electrolysis of CuSO4 aqueous solution using copper as cathode as well as anode the substance which is deposited at cathode is( )H2SO4
( )Oxygen
( )Copper
( )Hydrogen
Single Answer
66An electrochemical cell in which a spontaneous oxidation reduction reaction generates electrical current is called( )Electrolytic cell
( )Galvanic or voltaic cell
( )Dry cell
( )All the above
Single Answer
67In the electolysis of aqueous solution of sodium nitrate, the ions which are reduced at the cathode are( )H3O+
( )Na+
( )OH-
( )NO^3-
Single Answer
68In the elctrolysis of aqueous solution of NaCl, the reaction which takes place at cathode is( )Reduction of Na+ ions
( )Reduction of H+ ions
( )Reduction of H2O molecules
( )Discharge of Cl- ions
Single Answer
69Purification of an impure copper is made by electrolytic cell, in which impure copper is anode and pure copper is cathode, and the electrolyte is( )H2SO4
( )CuSO4
( )ZnSO4
( )Na2SO4
Single Answer
70The cell which generates electicity as a result of spontaneous oxidation-reduction reaction is called( )Electrolytic cell
( )Nelson's cell
( )Galvanic cell
( )Down's cell
Single Answer
71The function of salt bridge in the galvanic or voltaic cell is to( )Carry out oxidation at anode
( )Carry out reduction at cathode
( )Carry out electrolysis
( )Prevent the net charge accumulation in either of the half cells
Single Answer
72In voltaic cell the elctrode reactions are reversed when( )Salt bridge is removed
( )Voltaic cell is connected to SHE
( )External circuit is replaced by a source of electricity
( )H2SO4 is added to cell
Single Answer
73When a metal is dipped in 1 molar of its solution at 298 K, then potential set up is called( )Standard selctrode potential
( )Electric charge
( )Ionization potential
( )Electroplating
Single Answer
74A standard hydrogen electrode is used as standard electrode of which electrode potential is arbitrarily taken as( )+1
( )-1
( )0.1
( )Zero
Single Answer
75The reduction potential of copper electrode is +0.34 V and that of Zn electrode is -0.76 V. When these two are coupled the emf of the cell is( )-0.42 V
( )+0.42 V
( )-1.10 V
( )+1.10 V
Single Answer
76Coupling of Pb with its Pb++/Pb=-0.13 V and Ag with Ag+/Ag=+0.80 V, the cell reaction is( )Ag+2Pb+----->Ag++ +2Pb
( )2Ag+ +Pb----->Pb++ +2Ag
( )Ag+ +Pb----->Ag+Pb^+
( )Ag+Pb^+----->Ag+ +Pb
Single Answer
77A cell reaction is 2Al+3Cl2------->2AlCl3 the cell is represented as( )Al(1.0 M)/Al+++ Cl-(1.0 M)/Cl2
( )Cl2/Cl (1.0 M) Al+++(1.0 M/Al)
( )2Cl-(1.0 M)/Cl2 Cl2 Al/Al++(1.0 M)
( )Al+++(1.0 M)Al Cl-(1.0 M)/Cl2
Single Answer
78Electrochemical series is a list of elements arranged into the increasing order of their( )Standard oxidation potential
( )Standard reduction potential
( )Cell voltage
( )Ionization potential
Single Answer
79The voltaic or galvanic cells which cannot be recharged are called( )Primary cells
( )Secondary cells
( )Infinite cells
( )Fuel cells
Single Answer
80The galvanic or voltaic cells which are recharged are called as( )Primary cells
( )Secondary cells
( )Dry cells
( )Infinite cells
Single Answer
81A cell having PbO2 as cathode and metallic lead as anode and electrolyte is 30% H2SO4, then this cell is called( )Car battery
( )Alkaline battery
( )Fuel cell
( )Dry cell
Single Answer
82Lead accumulators contain( )30% NaCl solution as electrolyte
( )30% HCl solution as electrolyte
( )30% H2SO4 solution as electrolyte
( )30% NaOH solution as electrolyte
Single Answer
83The difference of potential of a cell consisting of a particular electrode and standard hydrogen electrode is called( )Electrode potential
( )Standard cell potential
( )Half cell reaction
( )None of these
Single Answer
84Which statement is incorrect about Standard Hydrogen Electrode(SHE)( )Its oxidation and reduction potential is zero
( )It consists of Pt wire dipped in 1 molar HCl solution
( )The electrolyte is 1 molar NaOH solution
( )H2 gas is passed in it at 1 atmospheric pressure
Single Answer
85Which of the following takes place spontaneously( )MgCl2 + Zn-------->ZnCL2 + Mg
( )H2 + AgNO3------>2HNO3 + 2Ag
( )2AlCl3-------->2Al + 3 Cl2
( )I2 + 2KCl--------->2KI + Cl2
Single Answer
86Which one of the following is non-spontaneous( )Zn + CuSO4----->ZnSO4 + Cu
( )Pb + 2AgNO3------->Pb(NO3)2 + 2Ag
( )2FeCl3 + H2------>6HCl + 2Fe
( )Ni + CaCl2-------->NiCl2 + Ca
Single Answer
87Alkaline battery has voltage of( )4.5 V
( )3.5 V
( )2.5 V
( )1.5 V
Single Answer
88After replacing of car battery (lead accumulator) the density of H2SO4 is( )1.0 grams/cm3
( )1.15 grams/cm3
( )1.25 grams/cm3
( )2.15 grams/cm3
Single Answer
89A dry cell has porous Zn anode and MnO2 as cathode the electrolyte used is( )Ca(OH)2
( )NaOH
( )KOH
( )NH4OH
Single Answer
90In electronic watches or elctronic calculators the tiny batteries used are( )Alkaline battery
( )NICAD battery
( )Fuel cell
( )Silver oxide battery
Single Answer
91The overall cell reaction 2H2(g) + O2(g)------>2H2O(l) in which KOH is used as an electrolyte, the cell is called( )Alkaline battery
( )Dry cell
( )Fuel cell
( )Electrolytic cell
Single Answer
92Silver oxide battery has a voltage of( )2.0 V
( )1.5 V
( )2.5 V
( ).0 V
Single Answer
93Lead accumulator stops discharging current when( )Lead at anode is converted to PbO2
( )PbO2 at cathode converted to Pb
( )Both electrodes are completely covered with PbSO4
( )Both electrodes are completely covered with Pb(OH)2
Single Answer
94Which statement is incorrect for NICAD battery( )The electrolyte is alkali
( )Cd acts as anoe
( )MnO2 acts as electrolyte
( )NiO2 acts as cathode
Single Answer
95Which statement is correct for the fuel cell( )These cells operate at low temperature
( )No catalyst used for the formation of water
( )MnO2 is used as electrolyte
Single Answer
96The oxidation number of H is -1 in the compound( )H2O
( )H2BO3
( )NaOH
( )NaH
Single Answer
97In F2O the oxidation number of oxygen is( )-2
( )-1
( )+1
( )+2
Single Answer
98The oxidation number of Mn in KMnO4 is( )+2
( )+4
( )+6
( )+7
Single Answer
99The oxidation state of Cr in K2Cr2O7 is( )+3
( )+6
( )+9
( )+4
Single Answer
100In a compound an atom has negative oxidation states because( )Atom is negatively charged
( )Atom acts as cathode
( )Atom is more electronegative
( )Atom has lowest ionization energy
Single Answer
101An oxidizing agent in a chemical reaction is the substance which( )Loses electron
( )Gains electrons
( ) pH is changed
( )Ascts as catalyst
Single Answer
102In the reaction Cu + HNO3------>Cu(NO3)2 + NO + H2O the atom which is oxidized( )Cu
( )H
( )N
( )O
Single Answer
103Metals like Pb, Sn, Ni, Co and Cd react vry slowly with steam to produce H2 gas beacuse( )These have maximum reduction
( )These have minimum reduction potential values
( )Their reduction potential value are very close to SHE
( )Their ionization potential values are minimum
Single Answer
104Coinage metals like Au, Pt, Ag and Cu are the least reactive metals and don't liberate H2 gas when treated with acids because( )These have very high positive values of reduction potential
( )These have high negative values of reduction potential
( )Their ionization potentials are lowest
( )Their reduction potentials are close to SHE
Single Answer
105Metals like Fe, Mg, Al, Cr, Zn have more negative reduction potentials that is why( )These don't react with steam
( )These react very slowly with steam to lierate H2 gas
( )These react rapidly with steam to produce the metallic oxides and liberate H2 gas
( )These react with cold water violently
Single Answer
106Which statement is incorrect for balancing of redox reactions by ion-electron method( )The reaction is splitted into two reactions
( )H2O and H+ ions are added for acidic or neutral reaction to balance O and H atoms
( )To balance H, HCl is added
( )To balance O and H in the alkaline reaction OH- added
Single Answer
107Li has lowest reduction potential while the element with highest reduction potential is( )H
( )F
( )O
( )N
Single Answer
108In passage of electricity through aqueous solution of AgNO3 silver dissolves at anode to form Ag+, the electrodes are( )Silver metal
( )Pt metal
( )Graphite
( )Copper metal
Single Answer
109When aqueous solution of NaOH is electrolyzed using graphite electrodes, the product obtained at anode is( )O2 gas
( )H2 gas
( )Na metal
( )Na2O
Single Answer
110An electrolytic cell consisiting of chromic acid electrolyte using Al metal as anode , the product obtained at anode is( )Cr metal
( )H2 gas
( )Cr2O3
( )Anodized Al
Single Answer
111In the electrolysis of fused bauxite (Al2O3.2H2O) with fused Cryolite (Na3 AlF6) using carbon rods as anode, the product obtained at cathode is( )Na metal
( )F2 gas
( )Al metal
( )O2 gas
Single Answer
112F2, Cl2, Br2 and I2 lie below SHE in the electro chemical series that is why these( )Undergo reduction
( )Undergo oxidation
( )Liberate H2 gas with steam
( )None of these
Single Answer
113In KO2 the oxidation state of oxygen is( )-2
( )-1
( )+1/2
( )-1/2
Single Answer
114Fe displace Cu from CuSO4 solution because( )Fe is ferromagnetic
( )Fe is below Cu in electrochemical series
( )Fe is above Cu in electro chemical series
( )Fe exists in divalent state
Single Answer
115Zn does not displace Mg from MgSO4 solution because( )Zn is more electropositive than Mg
( )Zn is below Mg in electrochemical series
( )Zn is above Mg in electrochemical series
( )Zn is trivalent Mg is divalent
Single Answer
116Standard reduction of Zn=-0.76 V and that of Ni is -0.25 V. On coupling them by a salt bridge which of these will act as anode( )Salt bridge
( )Zn
( )Ni
( )None of these
Single Answer
117Which statement is correct for balancing of redox reactions by oxidation number method( )Equate the increase and decrease in oxidation state of the atoms
( )Electrons are added or subtracted to balance oxidation number
( )Split the reaction into two halves
( )Add H2O and H+ to balance O and H atoms
Single Answer
118In the raction Cr(OH)3 + NaOH + H2O2-------->Na2CrO4 + H2O balancing of O atoms is done by( )Adding H2O and H+ ions
( )Adding OH- ions
( )Adding O2 molecules
( )Adding O atoms
Single Answer
119A standard hydrogen elecrtode (S.H.E) consists of a platinized platinum eletrode dipped in 1 molar solution of H+ ions and hydrogen gas is passed at a pressure of( )One Pascal
( )One kilo Pascal
( )One atm
( )Ten atm
Single Answer
120The standard electrode reduction potential of Li in Li+ + e-------->Li is -3.045. This shows Li is( )A strong reducing agent
( )A strong oxidizing agent
( )Better oxidizing agent then hydrogen
( )Less reducing agent then hydrogen
Single Answer
121The reduction potential of I2=+0.535 V, Br2=+1.08 V, Fe=+0.77 V shows that( )Iodine can oxidise iron
( )Bromine can oxidise iron
( )Iodine can oxidise bromine
( )Iron can oxidise bromine
Single Answer
122The reduction potentials are Zn^2+/Zn=-0.76 V; Cu^2+/Cu=+0.34 V, what is the E cell for the spontaneous reaction( )-1.10 V
( )+1.10 V
( )-0.42 V
( )+0.42 V
Single Answer
123In the reaction 2Fe+3Cl2------>2FeCl3( )Fe is reduced
( )Fe is oxidized
( )Cl2 is oxidized
( )None of these
Single Answer
124In electrolysis of molten sodium chloride in Down's cell the reaction which occurs at cathode is( )2NaCl(l)------->2Na+(l)+2Cl-(l)
( )2Na+(l)+2e----->2Na(l)
( )2Cl-(l)----->Cl2(g)
( )4H2O(l)------->4H+(aq)+4OH-(aq)
Single Answer
125In the extraction of aluminum, bauxite is purified by dissolving alumina in concentrated aqueous solution of sodium hydroxide which converts it into( )Sodium oxide
( )Sodium aluminum hydroxide
( )Aluminum hydroxide
( )Sodium aluminate
Single Answer
126Aluminum hydroxide precipitate in the extraction f aluminum is heated. The reaction is( )4Al(OH)3(s)-----heat------>4Al(l)+6H2O(g)+3O2(g)
( )2Al(OH)3(s)------heat------>Al2O3(s)+3H2O(g)
( )4Al(OH)3(s)------heat----->4Al(s)+6H2O(g)+3O2(g)
( )2Al(OH)3(s)-------heat---->2Al(s)+3H2(g)+3O2(g)
Single Answer
127In the electrorefining of blistered copper; electrodes are suspended in a solution containing copper sulphate, sulphuric acid and hydrochloric acid. In this process( )Blistered copper acts as cathode and pure copper as anode
( )Anode and cathodes are made up of pure copper
( )Anode and cathode are made up of blistered copper
( )Blistered copper acts as anode and pure copper as cathode
Single Answer
128During the purification of blistered copper by electrolysis less reactive metals like platinum, gold and silver deposit as anode mud or anode sludge. While( )Cathodes are gradually consumed and anode grows in size
( )Anodes are gradually consumed and cathodes grow in size
( )Both anodes and cathodes are gradually consumed
( )Non of the electrode is consumed during the process
Single Answer
129Regarding electrolytic and voltaic cells the true statement is( )In voltaic cell a non-spontaneous reaction generates electric current
( )In voltaic cell a spontaneous reaction generates electric current
( )In electrolytic cell a spontaneous reaction generates electric current
( )In eletrolytic cell a non-spontaneous raction generates electric current
Single Answer
130All of the following statements about Daniell cell are incorrct except( )Copper losses electrons
( )Zinc ions gain electrons
( )Copper is oxideized and zinc is reduced
( )Zinc rod is suspended in zinc sulphate solution
Single Answer
131Having Daniell cell in miind the incorrect statement is( )Copper is reduced
( )Zinc is oxidized
( )Copper is in direct contact with copper sulphate solution
( )Daniel cell is rechargeable
Single Answer
132Mr.Chemist was studying Daniel cell for one hour. At the end he raised his head and exclaimed haaa!!!!( )Both zinc and copper are good conductors
( )None of them is able to drag electrons from the other
( )Zinc acts as anode and copper as cathode
( )Copper acts as anode and zinc as cathode
Single Answer
133Standard hydrogen electrode is connected with an unknown half cell. If standard hydrogen electrode acts as cathode then half reaction for standard hydrogen electrode be( )H2------->2H+ +2e
( )2H+ +2e----->H2
( )2H+ +2e------->2H
( )2H----->H2
Single Answer
134Oxidation state of manganese in KMnO4 is( )+5
( )+7
( )+3
( )+2
Single Answer
135Consider the following redox reaction: 3Cu+2HNO3+HNO3------>3Cu(NO3)2 + 2NO + H2O. In this reaction( )Copper losses 2 electrons and nitrogen gains 2 electrons
( )Copper gains 3 electrons and nitrogen gains 3 electrons
( )Copper losses 4 electron and nitrogen gains 4 electrons
( )Copper losses 6 electrons and nitrogen gains 6 electrons
Single Answer
136Consider the half reaction Cr2O7^2- +6e- ------->2Cr^3+. To balance charge in acidic medium( )14 H+ should be added to the right side
( )14 H+ should be added to the left side
( )12 H+ should be added to the right side
( )12 H+ should be added to the left side
Single Answer
137If cell potential is positive then reaction will be( )Non-spontaneous in the forward direction
( )Spontaneous in the forward direction
( )Spontaneous in the reverse direction
( )Non-spontaneous in the forward direction but spontaneous in the reverse direction
Single Answer
138Dry cell, alkaline cell and mercury cell are the types of( )Primary cells
( )Secondary cells
( )Fuel cells
( )Rchargeable cells
Single Answer
139In lead-acid storage batteries Pb and PbO2 acts as( )Electrolyte
( )Charge storage plates
( )Anode and cathode respectively
( )Cathode and anode respectively
Single Answer
140Anodic reaction for lead-acid storage batteries is( )Pb(s) + SO4^2-(aq)-------->PbSO4(s) + 2e
( )PbSO4(s) + 2e---------->Pb(s) + SO4^2-(aq)
( )Pb(s)-------->Pb^2+9aq) + 2e
( )Pb^2+(aq) +2e----->Pb(s)
Single Answer
141Reagarding batteries all of the following tatements are incorrect except that( )Mercury cell is primary cell while nickel cadmium cell is secondary cell
( )Mercury cell is secondary cell while nickel-cadmium cell is primary cell
( )Both mercury and nickel-cadmium cells are primary cells
( )Both mercury and nickel cadmium cells are secondary cells
Single Answer
142In a fuel cell reactants are continuously added and the products are continuously removed. Cell reaction for hydrogen-oxygen fuel cell is( )1/2 O2(g) + H2O(l) +2e-------->2OH-(aq)
( )H2(g) + 2OH-(aq)------->2H2O(l) + 2e
( )H2(g) + 1/2 O2(g)--------->H2O(l)
( )H+ (aq) + OH-(aq)------->H2O(l)
Single Answer
143Reduction potential of copper is greater than that of magnesium which means that the following reaction is spontaneous( )Cu^2+(aq) + 2e------->Cu(s)
( )Mg(s)------->mg^2+(aq) + 2e
( )Cu(s) + Mg^2(aq)--------->Cu^2+(aq) + Mg(s)
( )Cu^2+ + Mg(s)-------->Cu(s) + Mg^2+(aq)
Single Answer
144Consider the cell reaction Pb + 2Ag^+--------->Pb^2+ +2Ag. If a cell is made based on this equation then( )Lead will act as anode and silver as cathode
( )Lead will act as cathode and silver as anode
( )Silver will act as cathode because it has greater reduction potential
( )Lead will act as anode because it has lesser reduction potential
Single Answer
145Choose the correct statement( )Oxidation state of N in NO and N2O5 is +5 and +2 respectively
( )Oxidation state of N in NO and N2O5 is +1 and +5 respectively
( )Oxidation state of N in NO and N2O5 is +2 and +5 respectively
( )Oxidation state of N in NO and N2O5 is +2 and +4 respectively
Single Answer
146Which of the following statement is correct for the life period of a galvanic cell( )It increases with increase in concentration of cathodic solution
( )It increases with increase in concentration of anodic solution
( )It increases with increase in the size of the cathode
( )It increases with decrease in the size of the anode
Single Answer
147A spontaneous reaction is for a galvanic cell as non spontaneous reaction is for( )Nelson's cell
( )Down's cell
( )Electrolytic cell
( )Daniel cell
Single Answer