Conductance Of Electrolytic Solutions
Chapter Name : Electrochemistry |
Sub Topic Code : 102_12_03_05_05 |
Topic Name : Conductance Of Electrolytic Solutions |
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Sub Topic Name : Weak Electrolytes |
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Introduction
• Weak electrolytes like acetic acid have lower degree of dissociation at higher concentrations. • Change in ?m, molar conductivity, with dilution is due to increase in the degree of dissociation. • At any concentration c, if ? is the degree of dissociation, then it is equal to the ratio of molar conductivity ?m at the concentration c to limiting molar conductivity, ?m°.
Pre-Requisites:
Electrochemical cell, electrolyte, conductivity, molar conductivity
Activity:
Salt solution conducts electricity as it forms a large number of ions in the salt solution. Salts are therefore necessary for the human body as well
Real Life Question:
Why does salt solution conduct electricity but a vinegar solution does not?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Electrolyte | Electrolyte is a solution which conducts electricity. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Salt water, vinegar, bulb with a circuit | Dip a circuit bulb in a salt solution and then in normal water. Notice the intensity of the light in the bulb. Now dip the circuit bulb attached to a battery in vinegar and compare it with the intensity of the light bulb with that in salt solution. |
Real life uses :
Conductivity of ionic solutions such as important salt, are important for the human body.
Places to visit :
Garage, switchboard
Practical examples around us
| Examples | Explainations |
|---|---|
| Salt solution, vinegar | A salt solution conducts electricity while vinegar, a diluted form of acetic acid, does not as it is a weak electrolyte. |
What you learn in Theory:
Ëm°, limiting molar conductivity, for weak electrolytes is obtained by using Kohlrausch law of independent migration of ions.
What you learn in Practice:
Strong electrolytes have strong electrical conductivity due to the higher number of cations and anions in solutions. Weak electrolytes have low electrical conductivity.