NEET Chemistry Electrochemistry MCQs Set B

Question:  If

  will be

• a) 3x₂– 2x₁
• b) x₂– x₁ 
• c) x₂+ x₁
• d) 2x₁+ 3x₂

Answer: 3x₂– 2x₁

Question: In lead storage battery, the anode reaction is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following is cathodic reaction?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  Electrode potential data are given below

Based on the above data which statement(s) is incorrect?

• a) Fe²⁺ is stronger reducing agent than Br^–
• b) Fe²⁺ is stronger oxidising agent than Al
• c) Al is stronger reducing agent than Fe²⁺
• d) Br^– is stronger reducing agent than Alg

Answer:  Br^– is stronger reducing agent than Alg

Question: The coulombic charge on one mole electron is

• a) 1.6 × 10^–19 C 
• b) 96500 C
• c) 6.02 × 10^–23 C 
• d) 1.6 × 10^–23 C

Answer: 96500 C

Question:  The resistance of 0.0025 M solution of K₂SO₄ is 326 ohm. The specific conductance of the solution, if cell constant is 4.

• a) 4.997 × 10^–4
• b) 5.997 × 10^–7 
• c) 6.997 × 10^–4 
• d) 1.20 × 10^–2

Answer:  1.20 × 10^–2

Question:  The conductivity of four electrolytes P, Q, R, S in ohm^–1 cm^–1 are as follows P(5 × 10^–5), Q(1× 10^–10), R(7 × 10^–8);S(9.2 ×10^–3). The one which offers highest resistance to the passage of electric current is

• a) P
• b) S
• c) R
• d) Q

Answer: Q

Question:  Zn rod is placed in 100 mL of 1M CuSO₄ solution so that molarity of Cu²⁺ changes to 0.7 M. The molarity of SO₄^{– –} at this stage will be

• a) 0.8 M
• b) 1 M
• c) 0.7 M
• d) 1.8 M

Answer: 1 M

Question: A direct current deposits 54 g of silver (atomic mass = 108) during the electrolysis. The same quantity of electricity would deposit aluminium (atomic mass = 27) from aluminium chloride in molten state equal to

• a) 4.5 g
• b) 5.4 g
• c) 54 g
• d) 27 g

Answer: 4.5 g

Question:  The time taken by the galvanic cell which operates almost ideally under reversible conditions at a current of 10^–16A to deliver 1 mole of electron is

• a) 19.30 × 10²⁰ s
• b) 4.825 × 10²⁰ s
• c) 9.65 × 10²⁰ s
• d) 3.4 × 10¹¹ s

Answer:  9.65 × 10²⁰ s

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

Question: During the electrolysis of water 4 mol of electrons were transferred from anode to cathode. The total volume of gases produced at STP will be approximately

• a) 67.2 L
• b) 22.4 L
• c) 44.8 L
• d) 89.4 L

Answer: 67.2 L

Question: Which of the following can oxidise fluoride ions?

• a) O₃ 
• b) Cl₂
• c) Br₂
• d) No chemical substance

Answer: No chemical substance

Question: In SHE, the pH of the acid solution should be

• a) 7
• b) 14
• c) 0
• d) 4

Answer: 0

Question:  Electrolysis of H₂SO₄(conc.) gives the following at anode

• a) H₂  
• b) O₂
• c) H₂S₂O₃  
• d) H₂S₂O₈

Answer:  H₂S₂O₈

Question:  If the standard reduction potential E° for four divalent elements X, Y, Z, W are –1.46 V, –0.36V, 0.15 V and –1.24 V respectively then

• a) X will replace Z²⁺ from aqueous solution
• b) Y will replace Z²⁺ from aqueous solution
• c) W will replace Z²⁺ from aqueous solution 
• d) All statements are corret

Answer: All statements are corret

Question:  E.M.F. of Ni(s)|Ni²⁺ (aq) || Cu²⁺ (aq)|Cu(s) cell can be increased by

• a) Adding NH³ in the right half-cell 
• b) Increasing the conc. of Ni²⁺ ions
• c) Adding dimethyl glyoxime into the left half-cell
• d) Changing the electrolyte present in salt bridge

Answer: Adding dimethyl glyoxime into the left half-cell

Question:  For given cell;   ΔG is negative if

• a) C₁= C₂  
• b) C₁> C₂
• c) C₂> C₁ 
• d) Can't predicted

Answer: C₂> C₁ 

Question:  The emf of the cell, Zn|Zn²⁺|Ag⁺|Ag is independent of

• a) The volume of Zn²⁺ and Ag⁺ solution 
• b) The molarity of Cu²⁺ ions in solution
• c) The molarity of Ag⁺ions in solution
• d) Temperature

Answer:  The volume of Zn²⁺ and Ag⁺ solution 

Question:  Standard cell voltage for the cell Pb/Pb²⁺||Sn²⁺/Sn is –0.01V. If the cell is to exhibit Ecell= 0, the value of log [Sn²⁺] /[Pb²⁺] should be

• a) 0.33
• b) 0.5
• c) 1.5
• d) –0.5

Answer: 0.33

Question:  The voltage of a cell whose half cell reactions are given below is

• a) –2.03 V
• b) 1.36 V
• c) 2.71 V
• d) 2.03 V

Answer: 2.71 V

Question: The quantity of electricity required to reduce 12.3 g of nitro benzene to aniline assuming 50% current effeciency is

• a) 115800 C
• b) 57900 C
• c) 231600 C
• d) 28950 C

Answer: 115800 C

Question:  A 100 watt, 110 volt lamp is connected in series with an electrolytic cell containing CdSO₄ solution, the weight of Cd deposited by the current for 10 hrs is (At. wt. Cd = 112.4)

• a) 19.06 g
• b) 38.12 g
• c) 1.906 g
• d) 3.812 g

Answer: 19.06 g

Question:  The two platinum electrodes filted in a conductance cell are 1.5 cm apart while the cross sectional area of each electrode is 0.75 cm². What is the cell constant?

• a) 1.25 cm
• b) 0.5 cm
• c) 2.0 cm^–1
• d) 0.2 cm^–1

Answer:  2.0 cm^–1

Question: A current of 2.0 A is passed for 5 hours through a molten metal salt deposits 22.2 g of metal (At. mass: 177). The oxidation state of the metal in metal salt is

• a) +1
• b) +2
• c) +3
• d) +4

Answer: +3

Question:   The following facts are available

Which of the following statement is correct?

• a)

  

• b)

  

• c)

  

• d) Can’t predict

Answer:

Question:   The hydrogen electrode is dipped in a solution of pH = 3 at 25°C. The reduction potential of the electrode would be

• a) 0.177 V
• b) 0.087 V
• c) –0.177 V
• d) 0.059 V

Answer: –0.177 V

Question:

 for the cell is 1.10 V at 25°C. The equilibrium constant for the cell reaction is of the order of

• a) 10^–37
• b) 10³⁷ 
• c) 10^–17 
• d) 10¹⁷

Answer: 10³⁷ 

Question:  A current of 0.965 ampere is passed through 500 ml of 0.2 M solution of ZnSO₄ for 10 minutes. The molarity of Zn²⁺ after deposition of zinc is

• a) 0.1 M
• b) 0.5 M
• c) 0.8 M
• d) 0.194 M

Answer: 0.194 M

Question:  What will be the emf of the given cell?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Aqueous solution of which of the following compounds is the best conductor of electric current?

• a) Ammonia, NH₃  
• b) Fructose, C₆H₁₂O₆
• c) Acetic acid, C₂H₄O₂  
• d) Hydrochloric acid, HCl

Answer: Hydrochloric acid, HCl

Question: A device that converts energy of combustion of fuels like hydrogen and methane, directly into electrical energy is known as

• a) Ni-Cd cell
• b) Fuel cell
• c) Electrolytic cell
• d) Dynamo

Answer: Fuel cell

Question:  When 0.1 mol   is oxidised the quantity of electricity required to completely oxidise   is

• a) 96500 C
• b) 2 × 96500 C
• c) 9650 C
• d) 96.50 C

Answer: 9650 C

Question:   The weight of silver (At. Wt. = 108) displaced by a quantity of electricity which displaces 5600 mL of O₂ at STP will be 

• a) 5.4 g
• b) 10.8 g
• c) 54.0 g
• d) 108.0 g

Answer: 108.0 g

Question:   A button cell used in watches functions as following

The cell potential will be 

• a) 0.42 V
• b) 0.84 V
• c) 1.34 V
• d) 1.10 V

Answer: 1.10 V

Question:  At 25°C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm^–1 cm² mol^–1 and at infinite dilution its molar conductance is 238 ohm^–1 cm² mol^–1. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is 

• a) 20.800%
• b) 4.008%
• c) 40.800%
• d) 2.080%

Answer: 4.008%

Question: A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of electrode would be?

• a) 0.59 V
• b) 0.118 V
• c) 1.18 V
• d) 0.059 V

Answer: 0.59 V

Question:  Limiting molar conductivity of  is equal to

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:   Standard reduction potentials of the half reactions are given below

The strongest oxidising and reducing agents respectively are 

• a) F₂ and I^– 
• b) Br₂ and Cl^–   
• c) Cl₂ and Br^–  
• d) Cl₂ and I₂

Answer:  F₂ and I^– 

Question:   Molar conductivities  at infinite dilution of NaCl, HCl and CH₃COONa are 126.4, 425.9 and 91.0 S cm² mol^–1 respectively  for CH₃COOH 

• a) 425.5 S cm² mol^–1
• b) 180.5 S cm² mol^–1
• c) 290.8 S cm² mol^–1 
• d) 390.5 S cm² mol^–1

Answer:  390.5 S cm² mol^–1

Question:   The Gibb's energy for the decomposition of Al₂O₃ at 500°C is as follows

The potential difference needed for the electrolytic reduction of aluminium oxide (Al₂O₃) at 500°C is at least

• a) 4.5 V
• b) 3.0 V
• c) 2.5 V
• d) 5.0 V

Answer: 2.5 V

Question:  Standard electrode potential for Sn⁴⁺ / Sn²⁺couple is +0.15 V and that for the Cr³⁺ / Cr couple is –0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be 

• a) + 1.83 V
• b) + 1.19 V
• c) + 0.89 V
• d) + 0.18 V

Answer: + 0.89 V

Question: An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to

• a) Increase in ionic mobility of ions
• b) 100% ionisation of electrolyte at normal dilution
• c) Increase in both i.e. number of ions and ionic mobility of ions
• d) Increase in number of ions

Answer: Increase in ionic mobility of ions

Question:   For the reduction of silver ions with copper metal, the standard cell potential was found to be +0.46V at 25°C. The value of standard Gibbs energy, ΔG° will be (F = 96500 C mol^–1) 

• a) –89.0 kJ
• b) –89.0 J
• c) –44.5 kJ
• d) –98.0 kJ

Answer: –89.0 kJ

Question:   Consider the following relations for emf of a electrochemical cell

(a) emf of cell = (Oxidation potential of anode) – (Reduction potential of cathode)

(b) emf of cell = (Oxidation potential of anode) + (Reduction potential of cathode)

(c) emf of cell = (Reductional potential of anode) + (Reduction potential of cathode)

(d) emf of cell = (Oxidation potential of anode) – (Oxidation potential of cathode) Which of the above relations are correct? 

• a) (c) and (a)
• b) (a) and (b)
• c) (c) and (d)
• d) (b) and (d)

Answer: (b) and (d)

Question:  Given

(i) Cu²⁺ + 2e^– → Cu, E^o = 0.337 V

(ii) Cu²⁺ + e^– → Cu⁺, E^o = 0.153 V

Electrode potential, E^o for the reaction,

Cu⁺ + e^– → Cu, will be 

• a) 0.90 V
• b) 0.30 V
• c) 0.38 V
• d) 0.52 V

Answer: 0.52 V

Question:   Al₂O₃ is reduced by electrolysis at low potentials and high currents. If 4.0 × 10⁴ amperes of current is passed through molten Al₂O₃ for 6 hours, what mass of aluminium is produced? (Assume 100% current efficiency, At.mass of Al = 27 g mol^–1) 

• a) 8.1 × 10⁴ g
• b) 2.4 × 10⁵ g
• c) 1.3 × 10⁴ g
• d) 9.0 × 10³ g

Answer: 8.1 × 10⁴ g

Question:  The equivalent conductance of M/32 solution of a weak monobasic acid is 8.0 mhos cm² and at infinite dilution is 400 mhos cm². The dissociation constant of this acid is

• a) 1.25 × 10^–6
• b) 6.25 × 10^–4
• c) 1.25 × 10^–4
• d) 1.25 × 10^–5

Answer:  1.25 × 10^–5

Question: Kohlrausch's law states that at

• a) Infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte
• b) Finite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the naure of the other ion of the electrolyte
• c) Infinite dilution each ion makes definite contribution to equivalent conductance of an electrolyte depending on the nature of the other ion of the electrolyte
• d) Infinite dilution, each ion makes definite contribution to conductance of an electrolyte whatever be the nature of the other ion of the electrolyte

Answer: Infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte

Question:  Standard free energies of formation (in kJ/mol) at 298 K are –237.2, –394.4 and –8.2 for H₂O (l), CO₂(g) andpentane (g) respectively. The value of E°_cell  for the pentane-oxygen fuel cell is 

• a) 0.0968 V
• b) 1.968 V
• c) 2.0968 V
• d) 1.0968 V

Answer: 1.0968 V

Question:  On the basis of the following E° values, the strongest oxidizing agent is

• a) [Fe(CN)₆]^3–
• b) [Fe(CN)₆]^4–
• c) Fe²⁺ 
• d) Fe³⁺

Answer: Fe³⁺

Question:  The equilibrium constant of the reaction

Cu(s) + 2Ag⁺ (aq) →Cu²⁺(aq) + 2Ag(s) ; E°=0.46V at 298 K is 

• a) 4.0 × 10¹⁵
• b) 2.4 × 10¹⁰
• c) 2.0 × 10¹⁰
• d) 4.0 × 10¹⁰

Answer:  4.0 × 10¹⁵

Question: The efficiency of a fuel cell is given by

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:   If  

the standard EMF of the reaction  will be 

• a) 0.330 V
• b) 1.653 V
• c) 1.212 V
• d) 0.111 V

Answer: 1.212 V

Question:  A hypothetical electrochemical cell is shown below A|A⁺(xM)||B⁺(yM)|B, the emf measured is +0.20 V. The cell reaction is 

• a) A⁺ + B → A + B⁺
• b) A⁺ + e^–  → A ; B⁺ + e^–  → B
• c) The cell reaction cannot be predicted
• d) A + B⁺  → A⁺ + B

Answer:  A + B⁺  → A⁺ + B

Question:  4.5g of aluminium (at. mass 27 amu) is deposited at cathode from Al³⁺ solution by a certain quantity of electric charge. The volume of hydrogen produced at STP from H⁺ ions in solution by the same quantity of electric charge will be 

• a) 22.4 L
• b) 44.8 L
• c) 5.6 L
• d) 11.2 L

Answer: 5.6 L

Question:  A solution contains Fe²⁺, Fe³⁺ and I^– ions. This solution was treated with iodine at 35°C. E° for Fe³⁺/Fe²⁺ is +0.77 V and E° for I₂/2I^– = 0.536 V. The favourable redox reaction is

• a) I^– will be oxidised to I₂
• b) Fe²⁺ will be oxidised to Fe³⁺
• c) I₂ will be reduced to I^– 
• d) There will be no redox reaction

Answer:  I^– will be oxidised to I₂

Question:  Standard reduction potentials at 25°C of Li⁺ / Li, Ba²⁺ / Ba, Na⁺ / Na and Mg²⁺ / Mg are –3.05, –2.90, –2.71 and –2.37 volt respectively. Which one of the following is the strongest oxidizing agent?

• a) Ba²⁺
• b) Mg²⁺ 
• c) Na⁺
• d) Li⁺

Answer: Mg²⁺ 

Question: To protect iron against corrosion, the most durable metal plating on it, is

• a) Copper plating
• b) Zinc plating
• c) Nickel plating
• d) Tin plating

Answer: Nickel plating

Question:  An electrochemical cell is set up as :

Pt; H₂(1 atm) |HCl (0.1 M) || CH₃COOH (0.1M) |

H₂(1 atm) ; Pt. The e.m.f. of this cell will not be zero, because

• a) Acids used in two compartments are different
• b) e.m.f. depends on molarities of acids used
• c) The temperature is constant
• d) pH of 0.1 M HCl & 0.1 M CH₃COOH is not same

Answer:   pH of 0.1 M HCl & 0.1 M CH₃COOH is not same

Question:   Electrode potential for the following half-cell reactions are

Zn → Zn²⁺ + 2e^–; E° = + 0.76 V;

Fe → Fe²⁺ + 2e^–; E° = + 0.44 V

The EMF for the cell reaction Fe²⁺ + Zn → Zn²⁺ + Fe will be

• a) – 0.32 V
• b) + 1.20 V
• c) – 1.20 V
• d) + 0.32 V

Answer: + 0.32 V