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CBSE Questions for Class 12 Engineering Chemistry Electrochemistry Quiz 10 - MCQExams.com

Heated saw dust catches fire when a drop of concentrated nitric acid is added to it. This is due to
  •  dehydration
  • oxidation
  • reduction
  • dehydrogenation
Passage of three faradays of charge through an aqueous solution of AgNO3,CuSO4,Al(NO3)3 and NaCl will deposit metals at the cathode in the molar ratio of:
  • 1:2:3:1
  • 6:3:2:6
  • 6:3:0:0
  • 3:2:1:0
Which of the following forms vortex ring?
  • P2O5
  • PH3
  • NH3
  • None of the above
On passing electricity through dil.H2SO4 solution, the amount of substance liberated at the cathode and anode are in the ratio :
  • 16:1
  • 1:16
  • 1:8
  • 8:1
How many kgs of silver would be deposited at cathode if 0.0342dm3 of oxygen measured at NTP is liberated at the anode when silver nitrate solution is electrolyzed between platinum electrodes?(Given : Atomic masses of Ag = 108, O =16)
  • 0.22 gm
  • 0.44 gm
  • 0.66 gm
  • None of the above
For the half reaction 
B(s) B2++2e     E1=0.44V
and 
B2+ B3++e         E2=1.3V
What is E3 for the reaction 
3e+B+3 B(s):
  • 0.86V
  • 0.14V
  • 0.14V
  • 0.28V
How much electricity in terms of Faraday is required to produce 40.0 g of Al from molten Al2O3?
  • 1 Faraday
  • 2 Faraday
  • 3.2 Faraday
  • 4.44 Faraday
Which of the following will be most easily corroded in moist air?
  • Zn
  • Fe
  • Ni
  • Sn
Which among the following cell cannot be regenerated?
  • NiCd cell
  • Leclanche cell
  • All of the given
  • Lead storage cell
When an electric current is passed through acidified water, 112 ml of hydrogen gas at STP collects at the cathode in 965 seconds. What is the current passed, in ampere?
  • 1.0
  • 0.5
  • 0.1
  • 2.0
Find the charge of 48g of Mg2+ ions in coulombs.
  • 2.4×1023C
  • 6.82×105C
  • 3.86×105C
  • 1.93×105C
The specific conductance of 0.1N KCl solution at 23oC is 0.012ohm1cm1. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be:
  • 0.142cm1
  • 0.66cm1
  • 0.918cm1
  • 1.12cm1
Excess of silver nitrate solution is added to 100mL of 0.01M pentaaqua chloro chromium (III) chloride solution. The mass of silver chloride obtained in grams is: 
[Atomic mass of silver is 108]
  • 287×103
  • 143.5×103
  • 143.5×102
  • 287×102
According to electrochemical theory of corrosion involves:
  • cathodic dissolution of metal
  • cathodic deposition of metal
  • anodic dissolution of metal
  • anodic deposition of metal
10800C of electricity on passing through the electrolyte solution deposited 2.977 of metal with atomic mass 106.4gmol1 the charge on the metal cation is:
  • +4
  • +3
  • +2
  • +1
Number of coulombs required to liberate 0.5 mol of O2 is:
  • 19300
  • 193000
  • 96500
  • 9650
If the density of copper is 8.94g/cm3, the number of faradays required to plate an area (10cm×10cm) of thickness of 102 cm using CuSO4 solution as electrolyte is:
  • 0.1F
  • 0.28F
  • 0.4F
  • 0.5F
The ratio of volume of H2 and Cl2 evolved at NTP by electrolysis of aqueous solution of HCl is:
  • 1:3
  • 3:5
  • 1:1
  • 1:7
A current of 9.95 amperes flowing for 10 minutes, deposits 3g of metal. An equivalent weight of the metal is:
  • 12.5
  • 18.5
  • 21.5
  • 48.5
How many faradays are needed for reduction of 2.5 moles of Cr2O27 into Cr3+ ?
  • 15
  • 12
  • 6
  • 3
The standard electrode potential of the half cells is given below:
Zn2++2eZn;E=0.76V
Fe2++2eFe;E=0.44V
The emf of the cell Fe2+=ZnZn2++Fe
  • 1.54V
  • 1.54V
  • 0.32V
  • +0.19V
Amount of charge is required to convert 17 g H2O2 into O2.
  • 1 F
  • 2 F
  • 3 F
  • none of these
Given,
EAg+/Ag=+0.80V,ECo2+/Co=0.28V,ECu2+/Cu=+0.34V,EZn2+/Zn=0.76V
Which metal will corrode to greater extent?
  • Ag
  • Cu
  • Co
  • Zn
Identify the correct half cell reaction of the following:
Zn+CuSO4ZnSO4+Cu
  • SO24SO4+2e
  • Zn2++2eZn
  • CuCu2++2e
  • Cu2++2eCu
If a pieces of iron gains 10% of its mass due to partial rusting into Fe2O3 the percentage of total iron that has rusted is
  • 3
  • 13
  • 23.3
  • 25.67
For the half reaction
B(s)B2++2e         E1=0.44V
and  B2+B3++e    E2=1.3V
What is E for the reaction,
3e+B+3B(s)
  • 0.86 V
  • 0.14 V
  • 0.14 V
  • 0.28 V
The weight in grams of O2 formed at Pt anode during the electrolysis of aq. K2SO4 solution during the passage of one coulomb of electricity is:
  • 1696800
  • 896500
  • 3296500
  • 6496500
A current 9.65 ampere is passed through the aqueous solution NaCl using suitable electrodes for 1000 s. The amount of NaOH formed during electrolysis is:
  • 2.0 g
  • 4.0 g
  • 6.0 g
  • 8.0 g
For the reaction:
Fe2+(aq)+Ag+(aq)Ag(s)+Fe+3(aq)

Predict which change will decrease the cell voltage?
  • Increase the amount of Ag
  • Decrease the concentration of Ag+
  • Increase the concentration of Fe+3
  • Both B and C
The electrolysis of aqueous solution of CuBr2 using platinum electrode would leads to:
  • Cu at anode
  • Br2 gas at anode and O2 gas at cathode
  • Cu at cathode
  • H2 gas at cathode
The number of coulombs required to deposit 5.4g of Aluminium when the given electrode reaction is represented as Al3++3eAl.
  • 1.83×105C
  • 57900C
  • 5.86×105C
  • 3F
How many faraday charge is required to convert one mole of C6H5NO2 in to C6H5NH2?
  • 8
  • 12
  • 6
  • 32
Given that Cl2(g)+2e2Cl(aq) is the reduction half-reaction for the overall reaction 2Ag(s)+Cl2(g)2AgCl(s)
What is the oxidation half reaction?
  • Ag(s)Ag+(aq)+e
  • Ag(s)+Cl(aq)Ag(s)+e
  • Ag(s)+Cl2(g)+eAgCl(s)+Cl(aq)
  • 2Cl(aq)Cl2(g)+2e
From the following half-cell reaction and their potential, What is the smallest possible standard e.m.f spontaneous reaction?
PO34(aq)+2H2O(I)+2eHPO23+3OH(aq);Eo=1.05V
PbO2(s)+H2O(I)+2ePbO(S)+2OH(aq);Eo=+0.28V
IO3(aq)+2H2O(I)+4eIO(aq)+4OH(aq);Eo=+0.56V
  • +0.00
  • +0.74
  • +0.56
  • +0.28
The time taken by the galvanic cell which operates almost ideally under reversible conditions at a current of 1016 A to deliver 1 mole of electron is:
  • 19.30×1020s
  • 4.825×1020s
  • 9.65×1020s
  • 3.4×1011s
When molten lithium chloride (LiCl) is electrolyzed, lithium metal is formed at the cathode. If current efficiency is 75% then how many grams of lithium are liberated when 1930 C of charge pass through the cell? (Atomic weight : Li=7)
  • 0.105
  • 0.120
  • 0.28
  • 0.240
Which of the following is a strong electrolyte?
  • Ca(NO3)2
  • HCN
  • H2SO3
  • NH4OH
How many Faraday are required to reduce one mol of MnO4 to Mn2+?
  • 1
  • 2
  • 3
  • 5
A schematic representation of enthalpy changes for the reaction, Cgraphite + 12O2 (g) CO (g) is given below. The missing value is
1149882_fbd603b197ea4f9a9e6372c7975a3575.png
  • + 10.5 kJ
  • - 11.05 kJ
  • - 110.5 kJ
  • - 10.5 kJ
Three faradays of electricity are passed through molten Al2O3, aqueous solution of CuSO4 and molten NaCl taken in different electrolytic cells. The amount of Al Cu and Na deposited at the cathodes will be in the ratio of?
  • 1 mole :2 mole :3 mole
  • 3 mole :2 mole :1 mole
  • 1 mole :1.5 mole :3 mole
  • 1.5 mole :2 mole :3 mole
What is the charge of 96 amu of S2?
  • 2C
  • 3.2×1019C
  • 9.6×1019C
  • 6C
Aluminum is obtained by 

  • Heating alumina with iron
  • Heating alumina with coke
  • Electrolysis of alumina solution in molten cryolite
  • Electrolysis of fused aluminum chloride
How many Faraday charge is required for KMnO4Mn2+?
  • 3 F
  • 2 F
  • 5 F
  • 1 F
If the following half cells have the Eo values as
Fe+3+eFe+2; Eo=+0.77V and Fe+2+2eFe ;
 Eo=0.44V The Eo of the half cell is Fe+3+3eFe will be:
  • 0.33 V
  • 1.21 V
  • 0.04 V
  • 0.605 V
When ammonia is added to a solution, its pH is raised to 11. Which half-cell reaction is affected by the pH and by how much?
  • Eoxd will increase by a factor of 0.65 from Eoxd
  • Eoxd will decrease by a factor of 0.65 from Eoxd
  • Ered will increase by a factor of 0.65 from Ered
  • Ered will decrease by a factor of 0.65 from Ered
Electrolysis is :
  • reversible process
  • irreversible process
  • either reversible or irreversible
  • neither reversible or irreversible
Conductivity of water (in Ω1cm1) is 
  • 0.4
  • 0.04
  • 0.0004
  • 0.00004
Indicator electrode is
  • SHE
  • Calomel electrode
  • Ag/AgCl electrode
  • Quinhydrone electrode
The amount of chlorine produced per-second through electrolysis in a plate which consumes 100 kW power at 200V is: (Given: Electrochemical equivalent of chlorine =0.367×103 g/C)
  • 18.35g
  • 1.835g
  • 183.5g
  • 0.1835g
The time required to remove electrolytically one-fourth of Ag from 0.2 litre of 0.1 M AgNO3 solution by the current of 0.1 amp is:
  • 160 min
  • 80 min
  • 40 min
  • 320 min
0:0:3


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