NEET Chemistry Electrochemistry MCQs Set A

Question: Purpose of hydrogen-oxygen fuel cell is to

• a) Generate heat
• b) Create potential difference
• c) Produce high purity water
• d) Remove adsorbed oxygen from electrode surface

Answer: Create potential difference

Question: Fluorine is the best oxidising agent because it has

• a) Highest electron affinity
• b)

  

• c)

  

• d) Lowest electron affinity

Answer:

Question:

In the above chemical reaction

• a) Water is oxidised
• b) Silver is oxidised
• c) Silver is reduced
• d) Hydrogen is reduced

Answer: Silver is reduced

Question: Which of the following is not a strong electrolytes?

• a) NaCl
• b) KNO₃
• c) NH₄OH 
• d) FeSO₄

Answer: NH₄OH 

Question: The molar conductivity of strong electrolyte

• a) Increases on dilution slightly
• b) Does not change on dilution
• c) Decreases on dilution
• d) Depends on density of electrolyte itself

Answer: Decreases on dilution

Question: The amount of electricity that can deposit 108 g of silver from silver nitrate solution is

• a) 1 ampere
• b) 1 coulomb
• c) 1 faraday
• d) 2 ampere

Answer: 1 faraday

Question: The electrochemical cell stops working after sometime because

• a) The reaction reverse its direction
• b) One of the electrode completely vanishes
• c) Electrode potential of both the electrodes equalise
• d) Electrode potential of both the electrodes becomes zero

Answer: Electrode potential of both the electrodes equalise

Question: The conduction of electricity through the electrolyte solution is due to

• a) Movement of molecules of electrolyte
• b) Movement of ions of electolyte
• c) Movement of separate atoms
• d) Movement of particles of the solvent

Answer: Movement of ions of electolyte

Question: In which of the following cell the energy of combustion of the reaction is directly converted into electricity?

• a) Lechlanche cell
• b) Concentration cell
• c) Fuel cell
• d) Lead storage battery

Answer: Fuel cell

Question: Corrosion is basically

• a) Altered reaction in presence of H₂O
• b) Electrochemical phenomenon
• c) Union between two light metals and a heavy metal
• d) Self oxidation and reduction

Answer: Electrochemical phenomenon

Question: The equilibrium constant for a feasible cell reaction

• a) < 1
• b) 0
• c) = 0
• d) > 1

Answer: > 1

Question: In the galvanic cell, true statement

• a) Current flows from anode to cathode
• b) Anode is +ve terminal
• c) If E_cell< 0, it is a spontaneous reaction 
• d) Cathode is +ve terminal

Answer: Cathode is +ve terminal

More Questions..............................................

Question: Which of the following is not correct?

• a) Molar conductance of a solution increases with dilution
• b) Equivalent conductance increases with dilution
• c) Specific conductance increases with dilution
• d) At infinite dilution each ion (cation or anion) plays a definite role towards electrical conductance

Answer: Specific conductance increases with dilution

Question: As the dilution of an electrolyte increases

• a) Specific conductance decreases
• b) Molar conductance decreases
• c) Resistance decreases
• d) No change takes place in conductance

Answer: Specific conductance decreases

Question: Equivalent conductance of a weak electrolyte increases on dilution because of

• a) Increase in number of ions per unit volume
• b) Increase in molecular attraction
• c) Increase in degree of association
• d) Increase in degree of ionisation of the substance

Answer: Increase in degree of ionisation of the substance

Question: The variation of equivalent conductance of strong electrolyte with concentration is correctly shown in which figure?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A 0.1M solution of monobasic acid at specific resistance of r ohms-cm, its molar conductivity is

• a) 10/r
• b) 10r
• c) 10⁴/r 
• d) 10⁴r

Answer: 10⁴/r 

Question:  The number of Faradays required to deposit 1 g equivalent of aluminium (At.wt. 27) from a solution of AlCl₃

• a) 1
• b) 2
• c) 3
• d) 4

Answer: 1

Question:   Electrochemical equivalent of Cu in the reaction  

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  When dil. HNO₃ is electrolysed

• a) H₂(g) is formed at anode
• b) O₂ gas is formed at anode
• c) NO₂ is formed at anode  
• d) N₂ is formed at anode

Answer:  O₂ gas is formed at anode

Question:  The specific conductivity of 0.5N solution is 0.01287 ohm^–1 cm^–1. What would be its equivalent conductance?

• a) 257.4
• b) 2.574
• c) 25.74
• d) 0.2574 ohm^–1 cm² (g. eq)^–1

Answer: 25.74

Question:  The specific conductance of saturated solution of CaF₂ is 3.86 × 10^–5 mho cm^–1 and that of water used for solution is 0.15 × 10^–5. The specific conductance of CaF₂ alone is

• a) 3.71 × 10^–5
• b) 4.01 × 10^–5
• c) 3.7 × 10^–4
• d) 3.86 × 10^–4

Answer: 3.71 × 10^–5

Question:  What will be the molar conductance ‘Λ’, if resistivity is ‘x’ for 0.1 N H₂SO₄ solution?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  The conductivities at infinite dilution of NH₄Cl, NaOH and NaCl are 130, 218, 120 ohm^–1cm² eq^–1. If equivalent conductance of N/100 solution of NH₄OH is 10, then degree of dissociation of NH₄OH at this dilution is

• a) 0.005
• b) 0.043
• c) 0.01
• d) 0.02

Answer: 0.043

Question: The resistance of a N/10 KCl aqueous solution is 245Ω. If the electrodes in the cell are 4 cm apart and area having 7 cm² each, the molar conductance of the solution will be

• a) 233
• b) 2.33
• c) 23.32
• d) 0.233

Answer: 23.32

Question: For strong electrolytes the values of molar conductivities at infinite dilution are given below :

The molar conductance at infinite dilution for Ba(OH)₂ is

• a) 523 × 10^–4 Sm² mol^–1
• b) 52.3 × 10^–4 Sm² mol^–1
• c) 5.23 × 10^–4 Sm² mol^–1
• d) 6.23 × 10^–4 Sm² mol^–1

Answer: 523 × 10^–4 Sm² mol^–1

Question:  Three faraday of electricity is passed through three electrolytic cells connected in series containing Ag⁺, Ca²⁺ and Al⁺³ ions respectively. The molar ratio in which the three metal ions are liberated at the electrodes is

• a) 1 : 2 : 3
• b) 3 : 2 : 1
• c) 6 : 3 : 2
• d) 3 : 4 : 2

Answer: 6 : 3 : 2

Question:  Deduced from the following E° values of half cells, what combination of two half cells would result in a cell with the largest potential?

• a) (i) and (iii)
• b) (i) and (ii)
• c) (ii) and (iv)
• d) (iii) and (iv)

Answer: (i) and (ii)

Question:  E° values of Mg²⁺|Mg, Zn²⁺|Zn and Fe²⁺|Fe are –2.37 V, –0.76 V and –0.44 V respectively. Which of the following is correct ?

• a) Mg²⁺ oxidises Fe
• b) Zn oxidises Fe²⁺
• c) Zn reduces Mg²⁺
• d) Zn reduces Fe²⁺

Answer:  Zn reduces Fe²⁺

Question: The standard reduction potential value of three metallic cations X, Y and Z are 0.52, –3.303 and –1.18 V respectively. The order of reducing power of the corresponding metals is

• a) Y > Z > X
• b) X > Y > Z
• c) Z > Y > X
• d) Z > X > Y

Answer: Y > Z > X

Question: The maximum current can be drawn from which of the following cells?

• a)

  

• b)

  

• c)

  

• d) All of these

Answer:

Question:   The standard reduction potential of Pb and Zn electrodes are –0.126 and –0.763 volts respectively. The e.m.f. of the cell

Zn | Zn²⁺ (0.1 M) || Pb²⁺ (1 M) | Pb is

• a) 0.637 V
• b) < 0.637 V
• c) > 0.637 V
• d) 0.889

Answer: > 0.637 V

Question:  For given half cell;  ; on increasing [Al⁺³], the electrode potential

• a) Increases
• b) Decreases
• c) No change
• d) First increases then decreases

Answer: Increases

Question: During electrolysis of aqueous solution of a salt pH in the space near one of the electrodes is increased. Which of the following salt solution was electrolysed?

• a) KCl
• b) CuCl₂
• c) Cu(NO₃)₂
• d) CuSO₄

Answer: KCl

Question:  Calculate EMF of the cell

• a) 0.30 V
• b) 1.21 V
• c) 0.26 V
• d) 0.80 V

Answer: 0.26 V

Question:   If ΔG for the reaction is A⁺ + B^– → A²⁺ + B^2– is x, the ΔG for the reaction is

• a) x/2
• b) 2x
• c) x² 
• d) √x

Answer: x/2

Question:  Consider the following equations for a cell

Then

• a) x = y, K₁= K₂
• b) x = 2y, K₁² = K₂
• c) x = y, K₁² = K₂
• d) x₂ = y, K₁² = K₂

Answer:  x = y, K₁² = K₂

Question: The EMF of a chemical cell is positive when free energy change of reaction

• a) > 0
• b) < 0
• c) = 0
• d) No relationship of free energy change and e.m.f.

Answer: < 0

Question: Which of the following statement is incorrect?

• a) Electrons enter through cathode in an electrolytic cell
• b) Electrons leave through anode in an electrolytic cell
• c) Cations in the electrolytic cell move towards cathode and anions towards anode
• d) Cations are reduced at anode and anions are oxidised at cathode in an electrolytic cell

Answer: Cations are reduced at anode and anions are oxidised at cathode in an electrolytic cell

Question:  The mass of Cl₂ produced when 1A current is passed through NaCl solution for 30 minute is

• a) 0.33 g
• b) 0.66 g
• c) 0.33 mol
• d) 0.66 mol

Answer: 0.66 g

Question: The ionic mobility of alkali metal ions in aqueous solution is maximum for

• a) Na⁺
• b) K⁺
• c) Rb⁺
• d) Li⁺

Answer:  Rb⁺

Question: A current of 9.65 A flowing for 10 minutes, deposits 3.0 g of a metal. The equivalent weight of the metal is

• a) 10
• b) 30
• c) 50
• d) 96.5

Answer: 50

Question:  Hydrazene can be used in fuel cell   If ΔG° for this reaction is –600 kJ, what will be the E° for the cell?

• a) 1.25 V
• b) 1.50 V
• c) 1.57 V
• d) 1.75 V

Answer: 1.57 V

Question: Which of the following solution will have highest specific conductance?

• a) 0.01 M CH₃COOH
• b) 0.01 M NH₄OH 
• c) 0.01M NaCl
• d) 0.01M K₂SO₄

Answer:  0.01M K₂SO₄

Question: Saturated solution of KNO₃ is used to make salt bridge because

• a) Velocity of K⁺ is greater than that of NO₃^- 
• b) Velocity of NO₃^- is greater than that of K⁺
• c) Velocity of K⁺ and NO₃^- are nearly same
• d) KNO₃ is highly soluble in water

Answer: Velocity of K⁺ and NO₃^- are nearly same

Question:  The equivalent conductivity of 1M H₂SO₄ solution would be if specific conductance is 26 × 10^–2S cm^–1.

• a) 1.3 × 10² S cm² sq^–1
• b) 1.6 × 10² S cm^–1
• c) 13 S cm² mol^–1
• d) 1.3 × 103 S cm² mol^–1

Answer:  1.3 × 10² S cm² sq^–1

Question: The main factors which affect corroision are

• a) Position of metal in electrochemical series
• b) Presence of CO₂ in water
• c) Presence of impurities in metals
• d) All of these

Answer: All of these

Question:  If 9 g of H₂O is electrolyzed completely with 50% current efficiency

• a) 1 F of electricity will be needed
• b) 3 F of electricity is needed
• c) 5.6 L of O₂ at STP will be formed
• d) 11.2 L of O₂ at STP will be formed

Answer:  5.6 L of O₂ at STP will be formed

Question: During the recharging of lead acid storage cell the reaction at anode is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  Which of the following cannot envolve H₂ from dil acid?

• a) Pt
• b) Zn
• c) Mg
• d) Pb

Answer: Pt

Question:  If the density of copper is 8.94 g/cm3, the number of Faradays required to plate an area (10cm × 10cm) of thickness of 10^–2 cm using CuSO₄ solution as electrolyte is

• a) 0.1 F
• b) 0.28 F
• c) 0.4 F
• d) 0.5 F

Answer: 0.28 F

Question: An electrolytic cell is composed of Cu and Zn. A current of 9.65 A is drawn from a cell for 1 hour. Then the loss in mass at anode and gain in mass at cathode, respectively could be

• a) 11.77 g, 11.43 g
• b) 11.77 g, 10 g
• c) 22.86 g, 23.54 g
• d) 23.54 g, 22.86 g

Answer: 11.77 g, 11.43 g

Question:   Volume of gases evolved when dil. H₂SO₄ is electrolysed using 2F at STP

• a) 22.4 L
• b) 11.2 L
• c) 33.6 L
• d) 44.8 L

Answer: 33.6 L

Question:  2.5 faraday of electricity is passes through a solution of CuSO₄ . The number of gram eqivalents of copper deposited on the cathode will be

• a) 1
• b) 2
• c) 2.5
• d) 1.25

Answer: 2.5

Question:  The specific conductivity of N/10 KCl 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

• a) 4.616 cm^–1
• b) 1.166 cm^–1
• c) 2.173 cm^–1
• d) 3.324 cm^–1

Answer:  1.166 cm^–1

Question: Which of the following is a strong electrocyte?

• a) Ca(NO₃)₂
• b) HCN
• c) H₂SO₃
• d) NH₄OH

Answer:  Ca(NO₃)₂

Question: If equal quantities of electricity are passed through three voltameter containing FeSO₄, Fe₂(SO₄)₃ and Fe(NO₃)₃, then which of the following is not true?

• a) Amount of iron deposited in FeSO₄ and Fe₂(SO₄)₃ is equal
• b) Amount of iron deposited in Fe(NO₃)₃ is 2/3 of the amount of iron deposited in FeSO₄
• c) Amount of iron deposited in Fe₂(SO₄)₃ and Fe(NO₃)₃ are equal
• d) Same gas will evolve in all three cases at anode

Answer:  Amount of iron deposited in FeSO₄ and Fe₂(SO₄)₃ is equal

Question:  A solution is 1 molar in each of NaCl, CdCl₂, ZnCl₂ and PbCl₂ . To this Sn metal is added, which of the following is true?

• a) Sn can reduce Na⁺ to Na
• b) Sn can reduce Zn²⁺ to Zn
• c) Sn can reduce Cd²⁺ to Cd
• d) Sn can reduce Pb²⁺ to Pb

Answer: Sn can reduce Pb²⁺ to Pb

Question: Equivalent conductance of NaCl, HCl and CH₃COONa at infinite dilution are 126.45, 425.16 and 91ohm^–1 cm² respectively. The equivalent conductance of CH₃COOH at infinite dilution would be

• a) 101.38 ohm^–1 cm²
• b) 253.62 ohm^–1 cm²
• c) 389.71 ohm^–1 cm²
• d) 678.90 ohm^–1 cm²

Answer:  389.71 ohm^–1 cm²

Question:  An electrochemical cell has two half cell reactions as,

The cell voltage will be

• a) 2.71 V
• b) 2.03 V
• c) –2.71 V
• d) –2.03 V

Answer: 2.71 V