Electrochemistry

01

PYQ 2009

medium

chemistry ID: mht-cet-

Copper is a divalent metal. The value of its electrochemical equivalent is . Its atomic mass is

1

2

3

4

02

PYQ 2010

medium

chemistry ID: mht-cet-

electricity deposits

1

of

2

of

3

electrochemical equivalent of

4

half of electrochemical equivalent of

03

PYQ 2014

medium

chemistry ID: mht-cet-

Calculate molar conductivity of at infinite dilution if molar conductivity of, and at infinite dilution are,, respectively.

1

2

3

4

04

PYQ 2017

medium

chemistry ID: mht-cet-

What is the unit of conductivity ?

1

2

3

4

05

PYQ 2018

medium

chemistry ID: mht-cet-

During galvanization of iron, which metal is used for coating iron surface ?

1

Copper

2

Zinc

3

Nickel

4

Tin

06

PYQ 2020

easy

chemistry ID: mht-cet-

How much charge in coulombs is required for the reduction of one mole of Al to Al?

1

C

2

C

3

C

4

C

07

PYQ 2020

easy

chemistry ID: mht-cet-

Which of the following metals does NOT displace zinc from its solution?

1

Fe

2

K

3

Na

4

Al

08

PYQ 2020

medium

chemistry ID: mht-cet-

During the electrolysis of aqueous sodium chloride, the product obtained at the anode is

1

2

3

4

09

PYQ 2020

medium

chemistry ID: mht-cet-

Which metal from the following has the highest tendency to undergo oxidation?

1

Mg

2

Ag

3

Al

4

Fe

10

PYQ 2020

medium

chemistry ID: mht-cet-

During electrolysis of aqueous NaCl, the product obtained at cathode is

1

O (g)

2

Cl (g)

3

H O(g)

4

H (g)

11

PYQ 2020

medium

chemistry ID: mht-cet-

What is the molar conductivity at infinite dilution of, if the molar conductivity of ion and ion at infinite dilution is and respectively?

1

2

3

4

12

PYQ 2020

medium

chemistry ID: mht-cet-

Which among the following is an example of metal-sparingly soluble salt electrode?

1

2

3

4

13

PYQ 2020

medium

chemistry ID: mht-cet-

Van’t Hoff factor (i) for centimolal solution of is 3.333. What is its percentage dissociation?

1

80%

2

70%

3

33.33%

4

77.7%

14

PYQ 2020

medium

chemistry ID: mht-cet-

Aniline reacts with bromine water at room temperature to give

1

3-bromoaniline

2

2-bromoaniline

3

4-bromoaniline

4

2,4,6-tribromoaniline

15

PYQ 2020

medium

chemistry ID: mht-cet-

kg urea is dissolved in 1 litre of water and it is isotonic with 500 mL aqueous glucose solution. What is the amount of glucose present in solution? (Atomic mass: C = 12, H = 1, O = 16, N = 14)

1

3.45 g

2

1.8 g

3

4.60 g

4

2.25 g

16

PYQ 2020

medium

chemistry ID: mht-cet-

Which of the following pairs of moving phase and stationary phase respectively is correct for column chromatography?

1

Liquid, Solid

2

Solid, Liquid

3

Gas, Liquid

4

Gas, Solid

17

PYQ 2020

medium

chemistry ID: mht-cet-

Resistance of 0.1 M KCl solution in a conductivity cell is 300 ohm and conductivity is 0.013 S cm . What is the cell constant?

1

4.5 cm

2

3.0 cm

3

1.5 cm

4

3.9 cm

18

PYQ 2020

medium

chemistry ID: mht-cet-

The conductivity of 0.01 M salt solution is 1.061 \times 10 S cm . What is molar conductivity of the solution?

1

2

3

4

19

PYQ 2020

medium

chemistry ID: mht-cet-

The conductivity of NaI solution is and molar conductivity is . Calculate the concentration of NaI solution.

1

0.05 M

2

M

3

0.005 M

4

M

20

PYQ 2020

medium

chemistry ID: mht-cet-

Which of the following statements is true for electrolytic cell?

1

Oxidation occurs at positive electrode

2

Oxidation occurs at negative electrode

3

Anode is negative and cathode is positive electrode

4

Reduction occurs at positive electrode

21

PYQ 2020

medium

chemistry ID: mht-cet-

What is the number of =N-OH groups present in dimethyl glyoximato?

1

3

2

4

3

1

4

2

22

PYQ 2020

medium

chemistry ID: mht-cet-

Identify the correct decreasing order of relative tendency of metals to undergo oxidation from the following.

1

Cr>Al>Mg>Fe

2

Mg>Al>Cr>Fe

3

Al>Fe>Cr>Mg

4

Fe>Cr>Al>Mg

23

PYQ 2020

medium

chemistry ID: mht-cet-

What is the standard potential of the cell if and ?}

1

$0.101 V$

2

$-0.136 V$

3

$0.573 V$

4

$-0.753 V$

Official Solution

Correct Option: (3)

$Step 1: Identify cathode and anode. Copper has a higher standard reduction potential, so it acts as the cathode. Nickel acts as the anode. Step 2: Use cell potential formula. Step 3: Substitute the given values. Step 4: Conclusion. The standard potential of the cell is .$

24

PYQ 2020

medium

chemistry ID: mht-cet-

$What is the molar conductivity of 0.1 M NaCl if its conductivity is ?$

1

2

3

4

Official Solution

Correct Option: (1)

$Step 1: Understanding Molar Conductivity. Molar conductivity () is related to the conductivity () by the equation: where is the concentration of the solution. In this case, the concentration of NaCl is 0.1 M, and the conductivity is . Thus, the molar conductivity is: Step 2: Analyzing the options. (A) : Correct. This is the correct molar conductivity. (B) : Incorrect. This is the given conductivity, not the molar conductivity. (C) : Incorrect. This does not match the correct molar conductivity. (D) : Incorrect. This is too large. Step 3: Conclusion. The correct molar conductivity is, corresponding to option (A) .$

25

PYQ 2020

medium

chemistry ID: mht-cet-

$What is the common unit of conductivity if the dimensions are expressed in centimeter?$

1

2

3

4

Official Solution

Correct Option: (2)

$Step 1: Understanding Conductivity. The unit of conductivity is the reciprocal of resistance. If resistance is measured in ohms (), then conductivity has units of . Additionally, conductivity is typically measured per unit length (centimeter), which gives the unit . Step 2: Analyzing the options. (A) : Incorrect. This represents a unit of resistivity, not conductivity. (B) : Correct. This is the correct unit for conductivity when expressed in terms of centimeter. (C) : Incorrect. This represents a unit of resistivity, not conductivity. (D) : Incorrect. This unit does not correctly represent conductivity. Step 3: Conclusion. The correct unit for conductivity is, corresponding to option (B) .$

26

PYQ 2020

medium

chemistry ID: mht-cet-

$What is the conductivity of 0.01 M NaCl solution if resistance and cell constant of NaCl solution are 375 ohms and respectively at 298 K ?$

1

2

3

4

Official Solution

Correct Option: (2)

$Step 1: Formula for conductivity. Conductivity () is given by: Step 2: Substitution of given values. Step 3: Calculation. Step 4: Conclusion. Therefore, the conductivity of the solution is .$

27

PYQ 2020

medium

chemistry ID: mht-cet-

$The standard emf of Daniell cell is 1.10 volt. What is the maximum electrical work obtained from Daniell cell?$

1

$212.3 kJ$

2

$175.4 kJ$

3

$106.15 kJ$

4

$57.07 kJ$

Official Solution

Correct Option: (1)

$Step 1: Understanding the relationship. The maximum electrical work () that can be obtained from a cell is given by the formula: where is the number of moles of electrons transferred, is the Faraday constant (), and is the standard emf of the cell. Using the values for the Daniell cell, the maximum electrical work is calculated as: Step 2: Analyzing the options. (A) 212.3 kJ: Correct — This is the correct maximum electrical work obtained from the Daniell cell. (B) 175.4 kJ: Incorrect. This value does not correspond to the correct calculation. (C) 106.15 kJ: Incorrect. This is not the correct electrical work. (D) 57.07 kJ: Incorrect. This value does not match the calculation. Step 3: Conclusion. The correct answer is (A) 212.3 kJ, which is the maximum electrical work from the Daniell cell.$

28

PYQ 2020

medium

chemistry ID: mht-cet-

$Mixture of iodine and Sodium Sulphate is separated by .........$

1

$Sublimation$

2

$Chromatography$

3

$Differential extraction$

4

$Distillation$

Official Solution

Correct Option: (1)

$Step 1: Understanding sublimation. Sublimation is the process where a solid changes directly into a gas without passing through the liquid phase. Iodine is a substance that sublimes, making it separable from sodium sulfate through this process. Step 2: Analyzing the options. (A) Sublimation: This is the correct answer because iodine sublimes, allowing it to be separated from sodium sulfate. (B) Chromatography: Chromatography is used for separating components based on different affinities for a stationary phase, but it’s not suitable for this mixture. (C) Differential extraction: This technique involves separating based on solubility differences, not for sublimation. (D) Distillation: Distillation is used for separating liquids with different boiling points, but not for separating solids from salts. Step 3: Conclusion. The correct answer is (A) Sublimation, as iodine can be separated from sodium sulfate by sublimation.$

29

PYQ 2020

medium

chemistry ID: mht-cet-

$Which of the following alcohols needs acidic KMnO to convert it into aldehyde or ketone?$

1

$Ethanol$

2

$Propan -1-ol$

3

$Propan -2-ol$

4

$2-Methyl propan -2-ol$

Official Solution

Correct Option: (3)

$Step 1: Understanding the use of KMnO . KMnO is a strong oxidizing agent that can oxidize alcohols to aldehydes or ketones. Secondary alcohols like propan-2-ol are oxidized to ketones by KMnO, while primary alcohols can be converted into aldehydes. Step 2: Analyzing the options. (A) Ethanol: Ethanol is a primary alcohol and needs a stronger oxidizer to convert it to an aldehyde. (B) Propan-1-ol: Propan-1-ol is a primary alcohol, which requires KMnO for oxidation to an aldehyde, not a ketone. (C) Propan-2-ol: This is a secondary alcohol that reacts with KMnO to form acetone (a ketone). (D) 2-Methyl propan-2-ol: This is a tertiary alcohol, which is generally resistant to oxidation by KMnO . Step 3: Conclusion. The correct answer is (C) Propan-2-ol, which can be oxidized by KMnO to a ketone.$

30

PYQ 2020

medium

chemistry ID: mht-cet-

$In 2 hours, a certain current liberates 0.504 g hydrogen. How many grams of copper can be deposited by the same current flowing for the same time in a solution? (Molar mass of Cu,)$

1

2

3

4

Official Solution

Correct Option: (4)

$Step 1: Apply Faraday’s law of electrolysis. For the same quantity of electricity, the masses of substances liberated are proportional to their equivalent weights. Step 2: Calculate equivalent weights. Hydrogen: Copper (from): Step 3: Use proportionality relation. Step 4: Conclusion. The mass of copper deposited by the same current in the same time is .$

31

PYQ 2020

medium

chemistry ID: mht-cet-

$When dry cell is in use the change taking place at cathode is$

1

$Zn is oxidised$

2

$is reduced$

3

$ions are reduced$

4

$is oxidised$

Official Solution

Correct Option: (3)

$Step 1: Recall the components of a dry cell. In a dry cell, zinc acts as the anode, carbon rod is the cathode, and the electrolyte is a paste of and . Step 2: Identify the process at the cathode. At the cathode, reduction takes place. In a dry cell, ions from ammonium chloride take part in the reduction process. Step 3: Cathodic reaction. Thus, ammonium ions gain electrons and are reduced at the cathode. Step 4: Conclusion. The change occurring at the cathode during the working of a dry cell is the reduction of ions.$

32

PYQ 2020

medium

chemistry ID: mht-cet-

$Conductivity cell is filled with 0.01 M KCl gives a resistance of 484 and conductivity of 0.004141 cm at 25°C. What is the cell constant?$

1

$0.682 cm$

2

$0.341 cm$

3

$0.751 cm$

4

$0.510 cm$

Official Solution

Correct Option: (1)

$Step 1: Understanding the relationship. The cell constant is given by the formula: where Conductivity = 0.004141 cm and Resistance = 484 . We use this formula to calculate the cell constant. Step 2: Applying the values. Substituting the given values, we calculate the cell constant: Step 3: Conclusion. The correct answer is (A) 0.682 cm, which is the calculated cell constant.$

33

PYQ 2020

medium

chemistry ID: mht-cet-

$Chlorine is manufactured by$

1

$Ostwald process$

2

$Contact process$

3

$Haber process$

4

$Deacon process$

Official Solution

Correct Option: (4)

$Step 1: Understanding the Deacon process. The Deacon process is a method of producing chlorine gas from hydrochloric acid (HCl) using oxygen in the presence of a catalyst. Step 2: Analyzing the options. (A) Ostwald process: This is used to produce nitric acid from ammonia, not chlorine. (B) Contact process: This process is used to make sulfuric acid, not chlorine. (C) Haber process: The Haber process is used to synthesize ammonia, not chlorine. (D) Deacon process: Correct — The Deacon process is used to manufacture chlorine gas from hydrochloric acid. Step 3: Conclusion. The correct answer is (D) Deacon process, as it specifically involves the production of chlorine.$

34

PYQ 2020

medium

chemistry ID: mht-cet-

$Which of the following elements belongs to the first inner transition series?$

1

$Bk$

2

$Pu$

3

$Pr$

4

$Fm$

Official Solution

Correct Option: (3)

$Step 1: Understanding the first inner transition series. The first inner transition series refers to the elements in the Lanthanide series, which are from atomic number 57 (Lanthanum) to atomic number 71 (Lutetium). These elements are also known as the rare earth elements. Step 2: Analyzing the options. (A) Bk: This is incorrect. Bk (Berkelium) is part of the actinide series, not the lanthanide series. (B) Pu: This is incorrect. Pu (Plutonium) also belongs to the actinide series. (C) Pr: Correct — Pr (Praseodymium) is part of the first inner transition series, belonging to the lanthanides. (D) Fm: This is incorrect. Fm (Fermium) is part of the actinide series. Step 3: Conclusion. The correct answer is (C) Pr, as Praseodymium belongs to the first inner transition series (Lanthanide series).$

35

PYQ 2020

medium

chemistry ID: mht-cet-

$Which alkane is secreted by cockroaches to attract the opposite gender of its species?$

1

$Octane$

2

$Nonane$

3

$Undecane$

4

$Decane$

Official Solution

Correct Option: (3)

$Step 1: Understanding the role of alkanes in cockroach behavior. Cockroaches release certain alkanes as pheromones to communicate, particularly to attract mates. One such alkane is undecane, which is secreted by female cockroaches to attract males. Step 2: Analyzing the options. (A) Octane: Octane is not the alkane used by cockroaches for this purpose. (B) Nonane: Nonane is not involved in cockroach communication. (C) Undecane: Correct — Undecane is the alkane secreted by cockroaches for attracting mates. (D) Decane: Decane is also not involved in cockroach mate attraction. Step 3: Conclusion. The correct answer is (C) Undecane .$

36

PYQ 2020

medium

chemistry ID: mht-cet-

$When a system absorbs 8 kJ of heat and does 2.2 kJ of work on surroundings, calculate the internal energy change.$

1

$-10.2 kJ$

2

$10.8 kJ$

3

$8.0 kJ$

4

$5.8 kJ$

Official Solution

Correct Option: (4)

$Step 1: Understanding the first law of thermodynamics. The first law of thermodynamics states that the change in internal energy is equal to the heat absorbed by the system minus the work done by the system . The equation is: Given: Heat absorbed Work done on surroundings (work done by the system is positive) Step 2: Calculation. Step 3: Conclusion. The internal energy change is, so the correct answer is (D) 5.8 kJ .$

37

PYQ 2020

medium

chemistry ID: mht-cet-

$How many electrons flow when a current of 5 amp is passed through a cell for 200 sec?$

1

2

3

4

Official Solution

Correct Option: (4)

$Step 1: Using the formula for charge. The total charge is given by: Where: Thus, the total charge is: Step 2: Using the formula for the number of electrons. The number of electrons is calculated using the formula: Where is the charge of a single electron. Substituting the values: Step 3: Conclusion. The correct answer is (D) .$

38

PYQ 2020

medium

chemistry ID: mht-cet-

$If the conductivity of 0.08 M KCl solution is, what is the molar conductivity of the solution?$

1

$350$

2

$250$

3

$25.0$

4

$0.25$

Official Solution

Correct Option: (2)

$Step 1: Understanding molar conductivity. Molar conductivity is given by the formula: Where is the conductivity and is the concentration of the solution. Step 2: Calculation. Given that the conductivity is and the concentration is 0.08 M, the molar conductivity is: Step 3: Conclusion. The correct answer is (B) 250 .$

39

PYQ 2020

medium

chemistry ID: mht-cet-

$What is the cell constant of KCl solution at, if conductivity and resistance of the solution are and respectively?$

1

2

3

4

Official Solution

Correct Option: (1)

$Step 1: Write the formula for cell constant. The relation between conductivity, resistance, and cell constant is given by: Step 2: Substitute the given values. Step 3: Calculate the result. Step 4: Final conclusion. Hence, the cell constant of the given KCl solution is .$

40

PYQ 2020

medium

chemistry ID: mht-cet-

$Which among the following is an example of Metal - metal ion electrode?$

1

$Fe (aq.) | Fe (aq.) | Pt$

2

$Cl (aq.) | AgCl(s) | Ag$

3

$Zn (aq.) | Zn(s)$

4

$OH (aq.) | O, PO | Pt$

Official Solution

Correct Option: (3)

$Step 1: Understanding metal - metal ion electrode. A metal - metal ion electrode consists of a metal and its ion in equilibrium, with the metal electrode immersed in a solution of its own ions. The electrode potential is determined by this equilibrium. Step 2: Analyzing the options. (A) Fe (aq.) | Fe (aq.) | Pt: This is a metal - metal ion electrode, but it involves a platinum electrode because iron is in different oxidation states. It is a valid electrode but not the best example. (B) Cl (aq.) | AgCl(s) | Ag: This is a metal - salt electrode, not a metal - metal ion electrode. (C) Zn (aq.) | Zn(s): This is a typical metal - metal ion electrode where zinc metal is in equilibrium with zinc ions. (D) OH (aq.) | O, PO | Pt: This is a gas - metal ion electrode, not a metal - metal ion electrode. Step 3: Conclusion. The correct answer is (C) Zn (aq.) | Zn(s), as it is the best example of a metal - metal ion electrode.$

41

PYQ 2020

medium

chemistry ID: mht-cet-

$What is the relation between cell constant, conductivity, and electrical resistance?$

1

2

3

4

Official Solution

Correct Option: (2)

$Step 1: Understanding the formula. The cell constant is related to the electrical resistance, the cell length, and the conductivity. The cell constant is defined as the ratio of the distance between the electrodes (length) to the area of the electrodes. The relation is given by: Where: - is the length of the cell, and - is the electrical resistance. Step 2: Analyzing the options. (A) : This is incorrect because it does not accurately represent the relationship between the conductivity and resistance. (B) : This is correct. The correct relation between the cell constant, conductivity, and electrical resistance is, where is the cell length and is the resistance. (C) : This is incorrect, as it does not align with the proper relationship. (D) : This is also incorrect. Step 3: Conclusion. The correct answer is (B) .$

42

PYQ 2022

easy

chemistry ID: mht-cet-

$What is standard reduction potential of Cu 2+ | Cu (s) if E° of following cell is 0.46V ? Cu (s) | Cu 2+ (aqs) || Ag + (aq) | Ag (s) ( E o = 0.80V)$

1

$1.56 V$

2

$1.44 V$

3

$1.26 V$

4

$0.34 V$

Official Solution

Correct Option: (4)

$The overall cell potential, E°cell, is the difference between the reduction and oxidation potentials: E° cell = E° reduction - E° oxidation Given E° cell = 0.46V, and E° reduction = 0.80V, we can rearrange the equation to solve for E° oxidation : E° oxidation = E° reduction - E° cell E° oxidation = 0.80V - 0.46V = 0.34V Therefore, the standard reduction potential of Cu²⁺ | Cu (s) is 0.34V. The correct option is: (D) 0.34 V$

43

PYQ 2022

easy

chemistry ID: mht-cet-

$Which from following equations is correct for relation between standard cell potential and equilibrium constant?$

1

$E cell = log 10 K$

2

$E cell = log 10 K$

3

$E 0 cell = log 10 K$

4

$E cell = log 10 K$

Official Solution

Correct Option: (3)

$The correct equation for the relation between standard cell potential (E°cell) and equilibrium constant (K) is: E 0 cell = log 10 K This equation is known as the Nernst equation and is used to calculate the cell potential of an electrochemical cell under non-standard conditions. In the equation, "n" represents the number of moles of electrons transferred in the balanced redox reaction. Therefore, the correct answer is (C) E 0 cell = log 10 K.$

44

PYQ 2024

easy

chemistry ID: mht-cet-

$Molar conductivity of an electrolyte depends on which of the following factors?$

Official Solution

Correct Option: (1)

45

PYQ 2024

medium

chemistry ID: mht-cet-

$The metal that cannot be obtained by electrolysis of an aqueous solution of its salts is:$

1

2

3

4

Official Solution

Correct Option: (2)

$The process of obtaining metals by electrolysis of their aqueous salts depends on the reduction potentials of the metal ions compared to the reduction of water. If the reduction potential of the metal ion is more negative than that of water, then water will be reduced instead of the metal, and the metal cannot be obtained from the aqueous solution. Step 1: Compare Reduction Potentials. Let's look at the reduction potentials of calcium () and water: The reduction potential for calcium: The reduction potential for water: Since the reduction potential for calcium () is much more negative than that for water (), it is not favorable for calcium to be reduced from its aqueous solution. Instead, hydrogen gas will be preferentially produced at the cathode during electrolysis, and no calcium metal will be deposited. Step 2: Other Metals in the Options. Silver (Ag): The reduction potential for silver is positive, so it can easily be reduced from an aqueous solution. Copper (Cu): Copper also has a positive reduction potential, making its reduction favorable in aqueous solutions. Chromium (Cr): Chromium can be reduced under specific conditions, though it might require different electrolytic conditions. Conclusion: Since calcium has a highly negative reduction potential compared to water, it cannot be obtained by electrolysis of its aqueous salt solution. Therefore, the correct answer is . Thus, the metal that cannot be obtained by electrolysis of its aqueous salt solution is .$

46

PYQ 2024

medium

chemistry ID: mht-cet-

$Alkyl halide and aryl halide react in the presence of sodium metal and dry ether. The name of the reaction is?$

1

$Wurtz Reaction$

2

$Wurtz-Fittig Reaction$

3

$Fittig Reaction$

4

$Williamson Ether Synthesis$

Official Solution

Correct Option: (2)

$In the Wurtz-Fittig reaction, alkyl halides and aryl halides react in the presence of sodium metal in dry ether to form alkyl aryl compounds: Explanation: Wurtz Reaction involves only alkyl halides. Fittig Reaction involves only aryl halides. Williamson Ether Synthesis is unrelated to this reaction.$

47

PYQ 2025

medium

chemistry ID: mht-cet-

$Identify the reaction in which entropy change is positive ().$

1

2

3

4

Official Solution

Correct Option: (1)

$Step 1: Concept when disorder increases. This typically happens when: - Number of gaseous moles increases. - Phase changes from solid liquid gas. Step 2: Analysis - (A) Liquid reactant Liquid + Gas product. Moles of gas increase (). . - (B) Gas + Gas Solid. Moles of gas decrease. . - (C) moles gas moles gas. . - (D) moles gas moles gas. . Final Answer: (A)$

48

PYQ 2025

hard

chemistry ID: mht-cet-

$What is the standard electrode potential for the reduction half-reaction ?$

1

$+0.34 V$

2

$-0.34 V$

3

$+0.72 V$

4

$-0.72 V$

Official Solution

Correct Option: (1)

$The standard electrode potential for the reduction half-reaction is a well-known value, which is . Thus, the standard electrode potential for this reaction is +0.34 V.$

49

PYQ 2025

easy

chemistry ID: mht-cet-

$In an electrochemical cell, the standard electrode potential of is and that of is . What is the standard EMF of the cell formed by these electrodes?$

1

2

3

4

Official Solution

Correct Option: (2)

$The electromotive force (EMF) of an electrochemical cell is calculated using the standard electrode potentials of the cathode and anode: Where: - is the standard reduction potential of the electrode where reduction occurs, - is the standard reduction potential of the electrode where oxidation occurs. Given: - Standard electrode potential of, - Standard electrode potential of . In a galvanic cell, the electrode with the higher reduction potential undergoes reduction (acts as the cathode), and the electrode with the lower reduction potential undergoes oxidation (acts as the anode). Comparing the potentials: - (higher, so cathode), - (lower, so anode). The cell can be represented as: Calculate the EMF: The positive EMF indicates that the cell is spontaneous as written. Thus, the standard EMF of the cell is .$

50

PYQ 2025

medium

chemistry ID: mht-cet-

$What is the standard electrode potential of the half-reaction: Given that the standard electrode potential for the half-reaction: Also, the cell potential for the following reaction is : is .$

1

2

3

4

Official Solution

Correct Option: (1)

$Given: The standard electrode potential for the half-reaction: is The cell potential for the reaction: is Step 1: Use the cell potential formula The cell potential is related to the standard electrode potentials of the half-reactions by the equation: where: - is the standard electrode potential of the reduction half-reaction (the one gaining electrons), - is the standard electrode potential of the oxidation half-reaction (the one losing electrons). Step 2: Identify the half-reactions The reaction involves: - Copper () being reduced to solid copper () at the cathode. - Silver () being oxidized to at the anode. Therefore, we know: Step 3: Rearrange the formula to find Substituting the known values into the formula: Solving for : ✅ Final Answer: The standard electrode potential for the half-reaction is .$

51

PYQ 2025

medium

chemistry ID: mht-cet-

$Calculate the relative lowering of vapour pressure of solution containing 3 g urea in 50 g water. [molar mass of urea = 60 g mol]}$

1

$0.013$

2

$0.025$

3

$0.018$

4

$0.028$

Official Solution

Correct Option: (3)

$Step 1: Formula Relative lowering of vapour pressure ( ) (mole fraction of solute). Step 2: Calculate Moles (urea) (water) Step 3: Calculate Final Answer: (C)$

52

PYQ 2025

medium

chemistry ID: mht-cet-

$What is the percentage composition of nitrogen in ammonium nitrate ()?$

1

$18.5%$

2

$28.0%$

3

$35.0%$

4

$42.5%$

Official Solution

Correct Option: (1)

$Step 1: Calculate the molar mass of ammonium nitrate The molecular formula of ammonium nitrate is . The molar masses of nitrogen (N), hydrogen (H), and oxygen (O) are: - Nitrogen (N) = 14 g/mol, - Hydrogen (H) = 1 g/mol, - Oxygen (O) = 16 g/mol. The molar mass of is: Step 2: Calculate the mass of nitrogen in ammonium nitrate There are two nitrogen atoms in, so the mass of nitrogen is: Step 3: Calculate the percentage composition of nitrogen The percentage composition of nitrogen is: Answer: Therefore, the percentage composition of nitrogen in ammonium nitrate is . So, the correct answer is option (3).$

53

PYQ 2025

medium

chemistry ID: mht-cet-

$What is the standard electrode potential for the half-reaction ?$

1

$+0.34 V$

2

$-0.34 V$

3

$+1.10 V$

4

$0 V$

Official Solution

Correct Option: (1)

$Step 1: Understand the concept of standard electrode potential The standard electrode potential (E°) is a measure of the ability of a half-cell to gain or lose electrons relative to the standard hydrogen electrode (SHE), which is defined as 0 V. A positive potential indicates that the substance tends to gain electrons (reduction), while a negative potential indicates that the substance tends to lose electrons (oxidation). Step 2: Check the standard electrode potential of copper From standard reference tables, the standard electrode potential for the half-reaction is . Answer: Therefore, the standard electrode potential for the half-reaction is . So, the correct answer is option (1).$

54

PYQ 2025

medium

chemistry ID: mht-cet-

$Identify the pair of carbohydrates containing galactose as one of constituent in both of them.$

1

$Sucrose and Stachyose$

2

$Maltose and Raffinose$

3

$Raffinose and Stachyose$

4

$Lactose and Maltose$

Official Solution

Correct Option: (3)

$Concept: Carbohydrates are composed of monosaccharide units such as glucose, fructose, and galactose. To solve this, we must know the composition of common disaccharides and oligosaccharides. Step 1: Recall compositions of given carbohydrates. Sucrose = Glucose + Fructose no galactose Maltose = Glucose + Glucose no galactose Lactose = Glucose + Galactose contains galactose Raffinose = Galactose + Glucose + Fructose contains galactose Stachyose = Galactose + Galactose + Glucose + Fructose contains galactose Step 2: Check each option. (A) Sucrose (no galactose) + Stachyose (has galactose) Incorrect (B) Maltose (no galactose) + Raffinose (has galactose) Incorrect (C) Raffinose + Stachyose both contain galactose \checkmark (D) Lactose (has galactose) + Maltose (no galactose) Incorrect Step 3: Conclusion.$

55

PYQ 2025

medium

chemistry ID: mht-cet-

$Identify the product of following reaction.$

1

$Phenyl methanol and methanol$

2

$Methanol and benzoic acid$

3

$Methanoic acid and phenyl methanol$

4

$Methanoic acid and benzoic acid$

Official Solution

Correct Option: (3)

$Concept: This is a Cannizzaro reaction, shown by aldehydes without -hydrogen. Step 1: Check reactants. Formaldehyde â no -H Benzaldehyde â no -H Step 2: Reaction mechanism. One molecule is oxidized, another is reduced: Step 3: Identify products. Step 4: Conclusion. Answer = (C)$

56

PYQ 2026

medium

chemistry ID: mht-cet-

$What is the product obtained at the cathode during the electrolysis of molten NaCl?$

1

$Chlorine gas$

2

$Sodium metal$

3

$Sodium hydroxide$

4

$Hydrogen gas$

Official Solution

Correct Option: (2)

$Concept: Electrolysis is the process in which electrical energy is used to drive a non-spontaneous chemical reaction. During electrolysis: • Reduction occurs at the cathode • Oxidation occurs at the anode Molten sodium chloride dissociates into ions: Step 1: Identify the reaction at the cathode. At the cathode, reduction takes place. Sodium ions gain electrons. Step 2: Determine the product formed. The reduced species is sodium metal .$

57

PYQ 2026

easy

chemistry ID: mht-cet-

$In the electrolysis of molten NaCl, the product obtained at the cathode is:$

1

$Cl gas$

2

$Na metal$

3

$NaOH$

4

$H gas$

Official Solution

Correct Option: (2)

$Concept: Electrolysis is the process in which electrical energy is used to drive a non-spontaneous chemical reaction. • Cathode: Reduction occurs (gain of electrons) • Anode: Oxidation occurs (loss of electrons) In molten NaCl, only and ions are present because there is no water. Step 1: Identify the ions present in molten NaCl. Step 2: Reaction occurring at the cathode (reduction). At the cathode, sodium ions gain electrons: Thus, sodium metal is deposited at the cathode. Step 3: Reaction occurring at the anode. Chloride ions lose electrons: This produces chlorine gas at the anode. Therefore, the product formed at the cathode during electrolysis of molten NaCl is$

58

PYQ 2026

easy

chemistry ID: mht-cet-

$What is the SI unit of molar conductivity?$

Official Solution

Correct Option: (1)

59

PYQ 2026

easy

chemistry ID: mht-cet-

$What is the SI unit of molar conductivity?$

Official Solution

Correct Option: (1)

60

PYQ 2026

medium

chemistry ID: mht-cet-

$In the electrolysis of molten NaCl, the product obtained at the cathode is:$

1

$Cl gas$

2

$Na metal$

3

$NaOH$

4

$H gas$

Official Solution

Correct Option: (2)

$Step 1: Understanding the Question: The question asks to identify the substance formed at the negative electrode (cathode) during the electrolysis of liquid (molten) sodium chloride. Step 3: Detailed Explanation: 1. Components: Molten contains only and ions. Unlike aqueous, there is no water to compete for reduction or oxidation. 2. At the Cathode (Negative Electrode): Reduction occurs here. The positive ions move toward the cathode, where they gain electrons. Sodium metal is deposited or formed at the cathode. 3. At the Anode (Positive Electrode): Oxidation occurs here. The negative ions move toward the anode, where they lose electrons. Chlorine gas is evolved at the anode. Step 4: Final Answer: The product at the cathode during the electrolysis of molten is sodium (Na) metal.$

High-Yield Trend

Chapter Questions 60 MCQs

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Step 1: Use the cell potential formula

Step 2: Identify the half-reactions

Step 3: Rearrange the formula to find

✅ Final Answer:

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Chapter Questions
60 MCQs

Step 3: Rearrange the formula to find $E_%7B%5Ctext%7BCu%7D%5E%7B2%2B%7D%20%2F%20%5Ctext%7BCu%7D%7D$