Electrochemistry is an essential topic in the JEE Mains Chemistry syllabus, covering key concepts such as redox reactions, electrolysis, cell potential, Nernst equation, and electrochemical cells. For JEE aspirants, practicing Previous Year Questions (PYQs) is one of the most effective ways to understand the types of questions asked and to strengthen your grasp on this topic.
By solving PYQs related to electrochemistry, you can gain insights into the recurring question patterns, difficulty levels, and the important areas that need more focus. In this article, we will explore the significance of Electrochemistry in JEE Mains and how practicing PYQs can help you score better in this section, boost your problem-solving skills, and build confidence for the exam.
Here after Electrochemistry JEE mains PYQ along with their step-by-step solutions. By working through these questions, you'll not only reinforce your understanding of the key concepts but also improve your time management and problem-solving skills for the actual exam. Let’s dive into the questions and explore the solutions in detail.
1. In a hydrogen-oxygen fuel cell, combustioan of hydrogen occurs to
(a) generate heat
(b) create a potential difference between the two electrodes
(c) produce high purity water
(d) remove adsorbed oxygen from the electrode surface.
Solution:
The correct option for the given question is (b).
2. Conductivity (unit Siemen’s S) is directly proportional to the area of the vessel and the concentration of the solution in it and is inversely proportional to the length of the vessel then the unit of the constant of proportionality is
(a) Sm mol-1
(b) Sm2 mol-1
(c) S-2m2 mol1
(d) S2m2 mol1
Solution:
The correct option for the given question is (b).
3. Galvanization is applying a coating of
(a) Pb
(b) Cr
(c) Cu
(d) Zn
Solution:
The correct option for the given question is (d).
4. Identify the correct statement.
(a) Corrosion of iron can be minimized by forming contact with another metal with a higher reduction potential.
(b) Iron corrodes in oxygen-free water.
(c) Corrosion of iron can be minimized by forming an impermeable barrier at its surface.
(d) Iron corrodes more rapidly in saltwater because its electrochemical potential is higher.
Solution:
The correct option for the given question is (c).
5. A solution of Ni(NO3 )2 is electrolyzed between platinum electrodes using 0.1 Faraday electricity. How many moles of Ni will be deposited at the cathode?
(a) 0.10
(b) 0.15
(c) 0.20
(d) 0.05
Solution:
The correct option for the given question is (d).
6. EMF of a cell in terms of reduction potential of its left and right electrodes is
(a) E = Eleft – Eright
(b) E = Eleft + Eright
(c) E = Eright – Eleft
(d) E = –(Eright + Eleft)
Solution:
The correct option for the given question is (c).
7. For a cell reaction involving a two-electron change, the standard e.m.f. of the cell is found to be 0.295 V at 25°C. The equilibrium constant of the reaction at 25°C will be
(a) 1 × 10–10
(b) 29.5 × 10–2
(c) 10
(d) 1 × 1010
Solution:
The correct option for the given question is (d).
8. If φ denotes reduction potential, then which is true?
(a) E°cell = φright – φleft
(b) E°cell = φleft + φright
(c) E°cell = φleft – φright
(d) E°cell = –(φleft +φright)
Solution:
The correct option for the given question is (a).
9. The anodic half-cell of lead-acid battery is recharged using electricity of 0.05 Faraday. The amount of PbSO4 electrolyzed in g during the process is [Molar mass of PbSO4 = 303 g mol–1]
(a) 15.2
(b) 11.4
(c) 7.6
(d) 22.8
Solution:
The correct option for the given question is (c).
10. Calculate the standard cell potential (in V) of the cell in which the following reaction takes place. Fe2+ (aq) + Ag+ (aq) → Fe3+ (aq) + Ag(s)
Given that E°Ag+ /Ag = x V; E°Fe2+ /Fe = y V; E°Fe3+ /Fe = z V
(a) x – z
(b) x – y
(c) x + 2y – 3z
(d) x + y – z
Solution:
The correct option for the given question is (c).
11. The standard Gibbs energy for the given cell reaction in kJ mol–1 at 298 K is
Zn(s) + Cu2+ (aq) → Zn2+(aq) + Cu(s), E ° = 2 V at 298 K (Faraday’s constant, F = 96000 C mol–1) (a) –192
(b) 192
(c) –384
(d) 384
Solution:
The correct option for the given question is (c).
12. Consider the statements S1 and S2:
S1: Conductivity always increases with a decrease in the concentration of electrolytes.
S2: Molar conductivity always increases with a decrease in the concentration of electrolytes. The correct option among the following is
(a) both S1 and S2 are wrong
(b) both S1 and S2 are correct
(c) S1 is wrong and S2 is correct
(d) S1 is correct and S2 is wrong.
Solution:
The correct option for the given question is (c).
13. If the standard electrode potential for a cell is 2 V at 300 K, the equilibrium constant (K) for the reaction,
Zn(s) + Cu2 + (aq) Zn2 + (aq) + Cu(s)
at 300 K is approximately (R = 8 J K–1 mol–1, F = 96500 C mol–1)
(a) e–80
(b) e 160
(c) e –160
(d) e 320
Solution:
The correct option for the given question is (b).
14. When during electrolysis of a solution of AgN03 9650 coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be
(a) 10.8 g
(b) 21.6 g
(c) 108 g
(d) 1.08 g
Solution:
The correct option for the given question is (a).
15. The correct order of E0M2+/M values with negative sign for the four successive elements Cr, Mn, Fe and Co is
(a) Mn > Cr > Fe > Co
(b) Cr > Fe > Mn> Co
(c) Fe > Mn > Cr > Co
(d) Cr > Mn > Fe > Co
Solution:
The correct option for the given question is (a).
Chemistry earlier years papers gives a thought of around 80 % of what is generally anticipated to come next jee man. Still, science in jee principle is simple when contrasted with different subjects, so read great reference books and score well.
The Nernst equation in NCERT is a key formula used to calculate the potential of an electrochemical cell under non-standard conditions, where the concentrations of reactants and products are not equal to 1 M. This equation helps determine the cell potential based on the concentrations of ions involved in the reaction. It is derived from the Gibbs free energy equation and is expressed as:
E = Eo - &dfrac;0.0591}{n} log &dfrac{[ “products” ]}{[ “reactants” ]}
Where E is the cell potential, Eo is the standard electrode potential, n represents the number of electrons involved, and the concentrations of products and reactants are also considered in the equation.
In simple terms, electrochemistry is the branch of chemistry that explores the relationship between electrical energy and chemical reactions. It studies how chemical reactions can produce electricity, as seen in batteries, and how electricity can drive chemical changes, as in the process of electrolysis. Electrochemistry is primarily concerned with oxidation (loss of electrons) and reduction (gain of electrons) reactions, which are fundamental in the functioning of electrochemical cells like batteries and fuel cells.
