ELECTROCHEMISTRY MCQs
Which relation corresponds to Faradays’ law of electrolysis?
- ΔF = -nFE°
- E = mc2
- E = hu
- m = Zt
m = Zt
Electrochemistry
Which statement is not true with reference to cell constant?
- The dimensions of cell constant is cm
- Specific conductance does not vary with concentration
- It is measured with KCl solution
- It is helpful and used to determine the specific conductance
Specific conductance does not vary with concentration
Which solids is a better ‘conductor of electricity?
- Pure NaCl crystals
- Sulfur
- Diamond
- Graphite
Graphite
____ is the device that converts the energy of fuel directly into electrical energy.
- Galvanic cell
- Electrolytic
- Concentration cell
- Fuel cell
Fuel cell
When some quantity of electricity is passed through two electrolytic cells, the ratio of the mass of the products obtained at the cathode is the same as the ratio of their
- Equivalent masses
- Atomic masses
- Densities
- Atomic numbers
Equivalent masses
The blue color of CuSO, disappears on adding Zn granules to it. It is because of
- Oxidation of Cu atom
- Oxidation of Zn2+
- Reduction of Zn2+
- Reduction of Cu2 +
Reduction of Cu2+
Which statement is not true with reference to ionic conductors?
- Ionic conductance is due to movement of the ions
- It decreases with rise in temperature
- It involves oxidation reduction reaction
- It involves the of matter
It decreases with rise in temperature
The unit of specific conductance will be
- Mho cm
- Ohm cm
- Ohm cm-1
- S cm-1
S cm-1
The conductance of 1 cm³ of an electrolyte solution is called its
- Specific resistance
- Molar conductance
- Specific conductance
- Equivalent conductance
Specific conductance
Which ion has high mobility in aqueous solution?
- K+
- Al+++
- Ca++
- H+
H+
Which solutions of NaCl will have the highest specific conductance?
- 0.001 N
- 0.01 N
- 1.0 N
- 0.1 N
1.0 N
Electrolytic conduction is due to the movement of which of the following?
- Electrons
- Molecules
- Atoms
- Ions
Ions
Which statement is not true with reference to Arrhenius theory of electrolytic dissociation?
- Electrolytes dissociate into charged species called ions in aqueous solution
- The ions are not free to move
- The extent of dissociation also depends on the temperature of the electrolyte
- The extent of dissociation depends on the concentration of the electrolyte
The ions are not free to move
The branch of chemistry which is concerned with the interrelation of electrical and chemical energy is called
- Reaction dynamics
- Electrochemistry
- Surface chemistry
- Kinetics
Equivalent conductance is expressed in the units
- S cm² eq–¹
- S cm eq–¹
- S cm² eq–¹
- S cm–¹ eq–¹
S cm² eq–¹
The fraction of the total current carried by an ion is called its ____.
- Transport number
- Ionic mobility
- Limiting ionic conductance
- None of A, B, and C
Transport number
If for a solution of an electrolyte, t4 is the transport number of the cation, then what is will be the transport number of the anion t?
- t+/2
- 1 + t+
- 1 – t+
- (1 – t)/2
1 + t+
Which process forever involve an increase in oxidation number?
- Oxidation
- Decomposition
- Reduction
- Hydrolysis
Oxidation
Which statement is true?
- The transport number of a cation is equal to its equivalent conductance
- The transport number of an ion is inversely proportional to its mobility
- The sum of the transport numbers of all the ions present is a solution in unity
- The transport number of a cation is equal to that of the anion
The sum of the transport numbers of all the ions present is a solution in unity
In which compounds the oxidation numberr of Cl is +3?
- CIF3
- CIO3
- ICI
- HCIO4
CIF3
What happens during a reaction of copper with aqueous solution of silver nitrate?
- Silver atoms are reduced
- Cu ions are reduced
- Nitrate ions are reduced
- Silver ions are reduced
Silver ions are reduced
What is the unit for the cell constant?
- Ώ-1 cm-1
- cm2
- cm-1
- cm-3
cm-1
During the titration of weak acid against NaOH, the conductance of the solution after the neutralization point
- Is constant
- Increases
- Varies irregularly
- Decreases
Increases
According to the Debye-Huckel theory of strong electrolytes, an ion moving in an atmosphere of oppositely charged ions experiences a drag. This effect is called _____ .
- Concentration effect
- Electrophoretic effect
- Inter-ionic effect
- Asymmetric effect
Asymmetric effect
Which procedure permanently causes the oxidation number to decrease?
- Reduction
- Hydrolysis
- Oxidation
- Decomposition
Reduction
What is the oxidation number of I in HIO4?
- +7
- +3
- +5
- +6
+7
Which reaction is not a redox reaction?
- Na₂O+ H₂SO4 → Na₂SO4 + H₂O
- 2Na + O₂ → Na₂O₂
- SO₂+2H₂S → 2H₂O + S
- NO+ 2H₂S → 2HO + N
Na₂O+ H₂SO4 → Na₂SO4 + H₂O
What is the oxidation number of Mn in KMnO4?
- +5
- -7
- +7
- +3
+7
Which specie is the strongest oxidizing agent in their standard state?
- Cl–
- Fe2+
- Cu2+
- Co³+
Co³+
Which statement is not true with respect to electrolytic conductors?
- New products are shown at the electrodes
- A single stream of electrons flow from cathode to anode
- Positive temperature coefficient is observed for the conductance
- Ions are responsible to carry current
A single stream of electrons flow from cathode to anode
Which electrodes have E°red = 0?
- Cl2/Ag+, Aq)
- Cl2/Cl–, Pt
- H2/2H+, Pt
- Cu2+/Cu
H2/2H+, Pt
The species undergoing reduction in following reaction is Cr + 2H2O + C10 → Cr³+ +3Cl¯ +6OH¯
- CIO
- H₂O
- Cr
- CIT
CIO
Which is a cathodic reaction?
- Fe2+ → Fe2+
- 22H2O → 2OH + H2
- 4OH → 2H2O + O
- 2SO42- → SO82-
2H2O → 2OH + H2
From the of activity series, the ideal reducing agent among the following is?
- I– ions
- CI– ions
- Br– ions
- F– ions
I– ions
In the cell reaction Cu + 2Ag+ → Cu2+ + 2Ag the reduction half reaction is +2Ag(s)
- Cu – 2e → Cu
- 2Ag + 2e → 2Ag
- 2Ag → 2Ag+ + 2e
- Cu2+ + 2e → Cu
Cu2+ + 2e → Cu
The electrode Pt/Fe2+(C₁), Fe3+(C2) belongs to the type
- Gas electrodes
- Metal-metal insoluble salt electrode
- Amalgam electrodes
- Inert metal electrodes
Inert metal electrodes
According to the latest convention, the e.m.f. of a cell may be expressed in terms of the reduction potentials RHS electrode (ER) and LHS electrode (EL) as
- Ecell = EL – ER
- Ecell = ER/EL
- Ecell = ER + EL
- Ecell = ER – EL
Ecell = ER – EL
Oxidation number of S in H2SO4 is
- +8
- +4
- +6
- +2
+4
Which statement is not true regarding galvanic cells?
- Oxidation occurs at the anode
- Ions carry current inside the cell
- When the e.m.t. of the cell is positive cell reaction is spontaneous
- Electrons flow around the external circuit, from cathode to anode
Electrons flow around the external circuit, from cathode to anode
The mathematical equation E – E°= -RT/nF In Q where Q is the reaction quotient is called
- Nernst equation
- Free energy equation
- Helmholtz equation
- Newton’s equation
Nernst equation
The emf of the cell Zn Zn2+ || Ag|Ag is independent of
- Temperature
- The molarity of Zn ions in the solution
- The molarity of Ag+ ions in the solution
- The volume of Zn2+ and Ag+ solutions
The volume of Zn2+ and Ag+ solutions
For Which cells, the standard voltage is zero
- Daniel cell
- Fuel cell
- Electrolytic cell
- Concentration cell
Concentration cell
Cell potential depends on which of the following?
- Temperature
- Concentration of ions
- Nature of electrolyte
- All of A, B, and C
All of A, B, and C
The depolarizer helpful and used in dry cell batteries is
- NH4CI
- Na3PO4
- KOH
D MnO2
MnO2
In lead storage battery, the anode reaction is
- Pb2+ + 2e → Pb
- None of A, B, and C
- PbO + H2SO4 → PbSo4 + H2O
- Pb + H₂SO4 → PbS04 + 2H+ + 2e–
Pb + H₂SO4 → PbS04 + 2H+ + 2e–
The cell in which a non-spontaneous redox reaction takes place as a result of electricity is know as
- Voltaic cell
- Dry cell
- Daniel cell
- Electrolytic cell
Electrolytic cell
The process of burning of hydrogen in an environment of oxygen to form water can be described as
- Oxidation only
- Reduction only
- Hydrogenation of oxygen
- Redox reaction
Redox reaction
Reaction taking place at anode in galvanic cells is
- Reduction
- Oxidation
- Hydrolysis
- Ionization
Oxidation
A half-cell reaction is one that
- Forever oxidizes
- Goes only half way to completion
- Involves a half mole of the concentration of the solution
- Occurs at one electrode
Occurs at one electrode
The oxidation state of carbon in sucrose is
- Zero
- +3
- -4
- +4
Zero
Which metals cannot displace copper from copper sulfate solution?
- Magnesium
- Aluminum
- Sodium
- Iron
Iron
Concentration polarization arises because of the
- Different concentrations of solutions in the two half cells
- Variation in temperature during measurements
- Reversible nature of the cell
- Changes in the concentration of electrolyte around the electrode from bulk concentration
Changes in the concentration of electrolyte around the electrode from bulk concentration
In a standard Weston cell, the cathode is
- Cadmium amalgam
- Carbon
- Platinum
- Mercury
Mercury
Overall positive value of cell potential predicts that the process is
- Feasible
- Reversible
- Impossible
- Not feasible
Feasible
Which is a primary cell?
- Fuel cell
- Alkaline dry cell
- Daniel cell
- Lead accumulator
Alkaline dry cell
In superoxide, the oxidation number of oxygen is
- -1/2
- -1
- +1
- Zero
-1/2
In which compound the oxidation state of Cl is +5
- NaCl
- HOCI
- NaClO4
- NaClO3
NaClO3
When brine solution is electrolyzed Which ions get discharged at anode?
- Na+
- OH–
- H+
- CI–
CI–
Which is not reduction?
- Gain of electron
- Decrease in negative oxidation state
- Loss of oxygen
- Gain of hydrogen
Gain of hydrogen
In silver oxide battery anode is made up of which of the following?
- NiO2
- Cd.
- Ag2O
- Zn
Zn
In an electrolytic cell
- Electrical energy is converted into heat
- Electrical energy is converted into mechanical energy
- Electrical energy is converted into chemical energy
- Chemical energy is converted into electrical energy
Electrical energy is converted into chemical energy
When a lead storage battery is discharged
- Sulfuric acid is consumed
- Lead sulfate is consumed
- SO2 is evolved
- Lead is formed
Sulfuric acid is consumed
Faraday’s laws of electrolysis are related to
- Equivalent mass of the electrolyte
- Atomic number of anion
- Atomic number of the cation
- Speed of the cation
Equivalent mass of the electrolyte
When copper wire is placed in a solution of silver nitrate. The solution acquires a blue color. This is due to the formation of
- Cu+ ions
- Soluble complex of copper with silver nitrate
- Cu2+ ions
- Reduction of copper
Cu2+ ions
The electric charge for electrode depositio of one gram equivalent of a substance is
- One ampere per second
- 96500 coulombs per second
- One ampere per hour
- Charge on one mole of electrons
Charge on one mole of electrons
The reaction taking place in fuel cell is
- 2H2 + 4OH → 4H2O (l) +4e
- O2 – 2H2O +4e– → 4OH–
- Both A & B
- None of A, B, and C
Both A & B
Which is true for an electrochemical cell?
- H2 is anode and Cu is cathode
- Reduction occurs at the H2-electrode
- Oxidation occurs at Cu electrode
- H2 is cathode and Cu is anode
H2 is anode and Cu is cathode
A cell reaction is spontaneous if the cell potential is
- Positive
- Zero
- Negative
- Infinite
Positive
Identify the true statement regarding fuel cells.
- They are more efficient
- They are free from pollution
- They run till the reactants are active
- All of A, B, and C
All of A, B, and C
In Which the free energy of a chemical reaction is directly converted to electricity?
- Lead storage battery
- Lechlanche cell
- Concentration cells
- Fuel cells
Fuel cells
In a galvanic cell
- Chemical energy is converted into heat
- Electrical energy is converted into heat
- Chemical energy is converted into electrical energy
- Electrical energy is converted into chemical energy
Electrical energy is converted into chemical energy
Which has same oxidation state in all of its compounds?
- Be
- Cl
- P
- N
Be
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