During the electrolysis of molten sodium chloride, the time required to produce $0.10$ mol of chlorine gas using a current of $3$ amperes is
- 55 minutes
- 110 minutes
- 220 minutes
- 330 minutes
The Correct Option is B
Solution and Explanation
Electrolysis Process Calculation
During the electrolysis of water, the following reactions occur:
At the Cathode:
The reduction half-reaction at the cathode is:
\(2H_2O \rightarrow [2e^-] H_2 + 2OH^-\)
At the Anode:
The oxidation half-reaction at the anode is:
\(2Cl^- \rightarrow [2e^-] Cl_2 + 2e^-\)
Using the Formula to Calculate Time:
The formula for calculating the time required for electrolysis is given by:
\(\frac{W}{E} = \frac{It}{96500}\)
Where: - \( W \) is the weight of the substance being electrolyzed, - \( E \) is the equivalent weight of the substance, - \( I \) is the current, - \( t \) is the time in seconds, - 96500 is the Faraday constant (in coulombs per mole).
Substitute the given values into the equation:
\(0.1 \times 2 = \frac{3 \times t}{96500}\)
Simplifying for \( t \), we get:
\(t = 6433 \, \text{seconds}\)
Converting seconds to minutes:
\(t = 107.2 \, \text{minutes} \approx 110 \, \text{minutes}\)
Conclusion:
The time required for electrolysis is approximately \( 110 \, \text{minutes} \).
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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.