Measurement of salt concentration in water with an ohm meter

[klystron]

How can you meaure the salt concentration in water with an ohm meter.
Must the measurement be AC or DC ?
What type of electrodes must be used ?
What is the relationship between the resitance and the NaCl concentration ?

 

[dazhen]

Re: Measurement of salt concentration in water with an ohm m

You can make two electrodes with copper plates. Dip the electrodes into the salt solution and measure the resistance with ohmmeter. AC measurement will work better in this case. By converting the conductance (inverse of the resistance) to the concentration of salt, you can make a series of measured salt solutions with concentration already known. Plot a figure of the relation between salt concentration and solution resistance (I suspect the relation is linear). Then drop your measured resistance of the unknown salt concentration solution on the figure. You can find the value you want. (Remember during the measurements, keep the seperation between two electrodes fixed).