Based on standard electrode potential values, suggest which of the following reactions would take place? (Consult the book for E\degree value).
(i) Cu + Zn2+→ Cu2+ + Zn
(ii) Mg + Fe2+→ Mg2+ + Fe
(iii) Br2 + 2Cl-→ Cl2 + 2Br-
(iv) Fe + Cd2+→ Cd + Fe2+
(i) Cu + Zn2+→ Cu2+ + Zn
Here Cu undergoes oxidation so it acts as anode and Zn acts as the cathode. So from the table
For cathode E°cathode = -0.76 V
For anode E°anode = 0.52 V
E°cell = -0.24V
As the EMF of the cell is negative the given reaction will not occur spontaneously if they were to form a cell placed as electrodes.
(ii) Mg + Fe2+→ Mg2+ + Fe
Similarly, we can say that Mg undergoes oxidation and Fe undergoes reduction.
E°cathode = -0.44 V
E°anode = -2.36 V
E°cell = +1.92V
Positive EMF implies that the reaction will give out energy and attain stability, thus it will occur spontaneously. So the given redox reaction will occur.
(iii) Br2 + 2Cl-→ Cl2 + 2Br-
Here Br undergoes reduction thus acting as cathode and Cl acting as the anode.
For cathode E°cathode = 1.09 V
For anode E°anode = 1.36 V
E°cell = -0.25
The negative potential prevents easy reaction, so the redox reaction will not occur.
(iv) Fe + Cd2+→ Cd + Fe2+
Fe is the cathode and Cd is the anode
For cathode E°cathode = -0.44 V
For anode E°anode = -0.40 V
E°cell = -0.04v
The negative potential prevents easy reaction, so the redox reaction will not occur.
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All Study Material
- JEE Main
- Exam Pattern
- Previous Year Papers
- PYQ Chapterwise
- Physics
- Kinematics 1D
- Kinemetics 2D
- Friction
- Work, Power, Energy
- Centre of Mass and Collision
- Rotational Dynamics
- Gravitation
- Calorimetry
- Elasticity
- Thermal Expansion
- Heat Transfer
- Kinetic Theory of Gases
- Thermodynamics
- Simple Harmonic Motion
- Wave on String
- Sound waves
- Fluid Mechanics
- Electrostatics
- Current Electricity
- Capacitor
- Magnetism and Matter
- Electromagnetic Induction
- Atomic Structure
- Dual Nature of Matter
- Nuclear Physics
- Radioactivity
- Semiconductors
- Communication System
- Error in Measurement & instruments
- Alternating Current
- Electromagnetic Waves
- Wave Optics
- X-Rays
- All Subjects
- Physics
- Motion in a Plane
- Law of Motion
- Work, Energy and Power
- Systems of Particles and Rotational Motion
- Gravitation
- Mechanical Properties of Solids
- Mechanical Properties of Fluids
- Thermal Properties of matter
- Thermodynamics
- Kinetic Theory
- Oscillations
- Waves
- Electric Charge and Fields
- Electrostatic Potential and Capacitance
- Current Electricity
- Thermoelectric Effects of Electric Current
- Heating Effects of Electric Current
- Moving Charges and Magnetism
- Magnetism and Matter
- Electromagnetic Induction
- Alternating Current
- Electromagnetic Wave
- Ray Optics and Optical Instruments
- Wave Optics
- Dual Nature of Radiation and Matter
- Atoms
- Nuclei
- Semiconductor Electronics: Materials, Devices and Simple Circuits.
- Chemical Effects of Electric Current,