Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because
- zinc is lighter than iron
- zinc has lower melting point than iron
- zinc has lower negative electrode potential than iron
- zinc has higher negative electrode potential than iron
The Correct Option is D
Solution and Explanation
Electrochemical Series and Corrosion Protection
The standard reduction potentials for zinc and iron are given as:
\(E^{0}_{\text{Zn}^{2+}/\text{Zn}} = - 0.76 \, \text{V}\)
\(E^{0}_{\text{Fe}^{2+}/\text{Fe}} = - 0.76 \, \text{V}\)
Explanation:
Both zinc and iron have the same standard reduction potential of -0.76 V. However, zinc has a higher negative standard reduction potential (SRP), which means that zinc is more readily oxidized than iron. Therefore, in an electrochemical cell or corrosion process:
- Zinc (Zn) acts as the anode where it gets oxidized to zinc ions (\( \text{Zn}^{2+} \)) and loses electrons.
- Iron (Fe) acts as the cathode, where the electrons from zinc are accepted, and iron is protected from corrosion.
Thus, zinc protects iron by sacrificially oxidizing itself, making it a useful material for galvanizing or protecting iron surfaces from rusting.
Top Questions on Electrochemistry
For the given cell: \[ {Fe}^{2+}(aq) + {Ag}^+(aq) \to {Fe}^{3+}(aq) + {Ag}(s) \] The standard cell potential of the above reaction is given. The standard reduction potentials are given as: \[ {Ag}^+ + e^- \to {Ag} \quad E^\circ = x \, {V} \] \[ {Fe}^{2+} + 2e^- \to {Fe} \quad E^\circ = y \, {V} \] \[ {Fe}^{3+} + 3e^- \to {Fe} \quad E^\circ = z \, {V} \] The correct answer is:
- JEE Main - 2025
- Chemistry
- Electrochemistry
- Which of the following electrolyte can be used to obtain \( \text{H}_2\text{S}_2\text{O}_8 \) by the process of electrolysis?
- JEE Main - 2025
- Chemistry
- Electrochemistry
Copper is being electrodeposited from a CuSO\(_4\) bath onto a stainless steel cathode of total surface area of 2 m\(^2\) in an electrolytic cell operated at a current density of 200 A m\(^{-2}\) with a current efficiency of 90%. The mass of copper deposited in 24 h is _________ kg (rounded off to two decimal places). Given: Faraday's constant = 96500 C mol\(^{-1}\), Atomic mass of copper = 63.5 g mol\(^{-1}\).
- GATE MT - 2025
- Metallurgical Thermodynamics
- Electrochemistry
- The molar conductances of Ba(OH)$_2$, BaCl$_2$ and NH$_4$Cl at infinite dilution are 523.28, 280.0 and 129.8 S cm$^2$ mol$^{-1}$ respectively. The molar conductance of NH$_4$OH at infinite dilution will be
- WBJEE - 2025
- Chemistry
- Electrochemistry
- Given below are two statements :
1 M aqueous solution of each of $ Cu(NO_3)_2 $, $ AgNO_3 $, $ Hg_2(NO_3)_2 $; $ Mg(NO_3)_2 $ are electrolysed using inert electrodes, Given : $ E^0_{Ag^+/Ag} = 0.80V $, $ E^0_{Hg_2^{2+}/Hg} = 0.79V $, $ E^0_{Cu^{2+}/Cu} = 0.34V $ and $ E^0_{Mg^{2+}/Mg} = -2.37V $
Statement (I) : With increasing voltage, the sequence of deposition of metals on the cathode will be Ag, Hg and Cu
Statement (II) : Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statements, choose the most appropriate answer from the options given below :- JEE Main - 2025
- Chemistry
- Electrochemistry
Questions Asked in NEET exam
- Which one of the following can be explained on the basis of Mendel’s Law of Dominance?
A. Out of one pair of factors one is dominant and the other is recessive.
B. Alleles do not show any expression and both the characters appear as such in F2 generation.
C. Factors occur in pairs in normal diploid plants.
D. The discrete unit controlling a particular character is called factor.
E. The expression of only one of the parental characters is found in a monohybrid cross.
Choose the correct answer from the options given below:- NEET (UG) - 2024
- Mendel’s Laws Of Inheritance
- In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is 100x (kcal m-2)yr-1, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?
- NEET (UG) - 2024
- Ecosystems
- A light ray enters through a right angled prism at point P with the angle of incidence 30° as shown in figure. It travels through the prism parallel to its base BC and emerges along the face AC. The refractive index of the prism is :
- NEET (UG) - 2024
- Refraction Through A Prism
- Identify the set of correct statement:
A. The flowers of Vallisneria are colourful and produce nectar.
B. The flowers of waterlily are not pollinated by water.
C. In most of water-pollinated species, the pollen grains are protected from wetting.
D. Pollen grains of some hydrophytes are long and ribbon like.
E. In some hydrophytes, the pollen grains are carried passively inside water.
Choose the correct answer from the options given below- NEET (UG) - 2024
- The Flower
- Given below are two statements:
Statement I: In C3 plants, some O2 binds to RuBisCO, hence CO, fixation is decreased.
Statement II: In C4 plants, mesophyll cells show very little photorespiration while bundle sheath cells do not show photorespiration.
In the light of the above statements, choose the correct answer from the options given below:- NEET (UG) - 2024
- respiration in plants
Concepts Used:
Electrochemical Cells
An electrochemical cell is a device that is used to create electrical energy through the chemical reactions which are involved in it. The electrical energy supplied to electrochemical cells is used to smooth the chemical reactions. In the electrochemical cell, the involved devices have the ability to convert the chemical energy to electrical energy or vice-versa.
Classification of Electrochemical Cell:
Cathode
- Denoted by a positive sign since electrons are consumed here
- A reduction reaction occurs in the cathode of an electrochemical cell
- Electrons move into the cathode
Anode
- Denoted by a negative sign since electrons are liberated here
- An oxidation reaction occurs here
- Electrons move out of the anode
Types of Electrochemical Cells:
Galvanic cells (also known as Voltaic cells)
- Chemical energy is transformed into electrical energy.
- The redox reactions are spontaneous in nature.
- The anode is negatively charged and the cathode is positively charged.
- The electrons originate from the species that undergo oxidation.
Electrolytic cells
- Electrical energy is transformed into chemical energy.
- The redox reactions are non-spontaneous.
- These cells are positively charged anode and negatively charged cathode.
- Electrons originate from an external source.