JEE (Based on NTA Guidelines-IIT Engg.) Mains Chemistry Coaching Programs
πΉ Video Course 2024 (0 Lectures [0 Mins]): Offline Support
Click Here to View & Get Complete Material
Rs. 100.00
1 Month Validity (Multiple Devices)
β³ π― Online Tests (1 Tests [30 Questions Each]): NTA Pattern, Analytics & Explanations
Click Here to View & Get Complete Material
Rs. 100.00
3 Year Validity (Multiple Devices)
π Study Material (159 Notes): 2024-2025 Syllabus
Click Here to View & Get Complete Material
Rs. 350.00
3 Year Validity (Multiple Devices)
π― 144 Numeric, 2994 MCQs (& PYQs) with Full Explanations (2024-2025 Exam)
Click Here to View & Get Complete Material
Rs. 650.00
3 Year Validity (Multiple Devices)
Chemistry Class 12 NCERT Solutions: Chapter 3 Electrochemistry Part 6
Q: 7. Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration
Ans:
Conductivity of a solution is defined as the conductance of a solution of 1 cm in length and area of cross-section 1 sq. cm. The inverse of resistivity is called conductivity or specific conductance. It is represented by the symbol G. If k is resistivity, then we can write:
The conductivity of a solution at any given concentration is the conductance (G) of one unit volume of solution kept between two platinum electrodes with the unit area of cross-section and at a distance of unit length.
Conductivity always decreases with a decrease in concentration, both for weak and strong electrolytes. This is because the number of ions per unit volume that carry the current in a solution decreases with a decrease in concentration.
Molar Conductivity:
Molar conductivity of a solution at a given concentration is the conductance of volume V of a solution containing 1 mole of the electrolyte kept between two electrodes with the area of cross-section A and distance of unit length.
Now, (Volume Containing 1 mole of the electrolyte) .
Molar conductivity increases with a decrease in concentration. This is because the total volume V of the solution containing one mole of the electrolyte increases on dilution.
The variation of with for strong and weak electrolytes is shown in the following plot:
Q: 8. The conductivity of M solution of at is . Calculate its molar conductivity.
Answer:
Given,
β΄ Molar conductivity,
Q: 9. The resistance of a conductivity cell containing solution at K is . What is the cell constant if conductivity of solution at is
Ans:
Given,
Conductivity,
Resistance,
β΄ Cell constant