Electrical Conductivity of Fluids

In summary, conductivity is determined by the presence of mobile charge carriers, which can be either positive or negative ions. In solutions, negative ions are typically better conductors due to their "spare" electrons. However, in the case of the human body, positively charged ions such as Na+, K+, and Ca+ also play a role in electrical conductivity, but through a different process involving the movement of charges within neurons.
  • #1
Shelnutt2
57
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So it has always been my understanding that in order for something to electrically conductive it has to have more electrons than it needs. If the electrons can be easily shaken from their atoms, then it's conductive. The easier it is for the electron to move to the next atom the more conductive it is correct?

So then when trying to make a solution conductive it would be best to add negative ions correct? These negatively charged ions have a more "spare" electrons. Positive ions would make very bad conductors as they have more protons than electrons there for they don't have any "spare" or electrons that are in a higher orbit and easier to break loose. Am I wrong in my thinking?

So then for example, when adding salt to water, NaCl, as it becomes Na+ and Cl-, it's actually the Cl- that makes it more conductive? If you could remove the sodium ions, Na+, would it become even more conductive?

Recently in a biology text I read it mentioned how Na+, K+, Ca+ and others help increase the electrical conductivity in the body and are used in transmitting neurons. I'm not sure if there is just a different process going on in the body, involving active transportation and potentials and other things, or do positively charged ions really increase conductivity too?


Thanks
 
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  • #2
In NaCl, both Na+ and Cl- contribute to the electrical conductivity. The Na+ moves to the negative electrode and the Cl- moves to the positive electrode. Movement of negative charge in one direction is "effectively" the same current as positive charge moving in the opposite direction. The most important thing is that the charges are not stuck to specific locations, but are free to move.
 
  • #3
Shelnutt2 said:
So it has always been my understanding that in order for something to electrically conductive it has to have more electrons than it needs. If the electrons can be easily shaken from their atoms, then it's conductive. The easier it is for the electron to move to the next atom the more conductive it is correct?

So then when trying to make a solution conductive it would be best to add negative ions correct? These negatively charged ions have a more "spare" electrons. Positive ions would make very bad conductors as they have more protons than electrons there for they don't have any "spare" or electrons that are in a higher orbit and easier to break loose. Am I wrong in my thinking?

Yes. A much better criterion for conductivity would be the presence of mobile charge carriers.
 
  • #4
atyy said:
The most important thing is that the charges are not stuck to specific locations, but are free to move.

In general you are right, but this statement needs IMHO clarification.

Not the charges are free to move, but ions. Charge moves together with ion. "Charges are not stuck" can be (wrongly) understood as free electrons moving in the liquid. That's not the case.

Well, in some solutions that can be the case, but in the presence of water solvated electrons are about as common as kangaroos in Alaska.
 
  • #5
Shelnutt2 said:
Recently in a biology text I read it mentioned how Na+, K+, Ca+ and others help increase the electrical conductivity in the body and are used in transmitting neurons. I'm not sure if there is just a different process going on in the body, involving active transportation and potentials and other things, or do positively charged ions really increase conductivity too?
The electrical activity of neurons is completely different than what goes on in man made machines and electronics. Very briefly, when a neuron "fires" positive charges move from outside the neuron to inside the neuron. There is no flow of electrons along a conductor.

This site has some animation that illustrates this:

http://www.bris.ac.uk/synaptic/public/basics_ch1_2.html [Broken]
 
Last edited by a moderator:

1. What is electrical conductivity of fluids?

Electrical conductivity of fluids is a measure of how easily an electric current can pass through a fluid. It is the ability of a fluid to conduct electricity.

2. How is electrical conductivity of fluids measured?

Electrical conductivity of fluids is typically measured using a conductivity meter, which measures the resistance of the fluid to an electric current. The higher the conductivity, the lower the resistance, and vice versa.

3. What factors affect the electrical conductivity of fluids?

The electrical conductivity of fluids can be affected by a variety of factors, including the concentration of ions in the fluid, the temperature of the fluid, and the type of ions present in the fluid.

4. Why is the electrical conductivity of fluids important?

The electrical conductivity of fluids is important in many scientific and industrial applications. It can be used to determine the purity of a fluid, monitor the health of water bodies, and control the flow of electricity in various systems.

5. How can the electrical conductivity of fluids be increased?

The electrical conductivity of fluids can be increased by adding conductive substances, such as salts or acids, to the fluid. Additionally, increasing the temperature of the fluid can also increase its conductivity.

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