Saved Bookmarks
| 1. |
Explain measurement and calculation of resistivity of electrolytic solution. |
|
Answer» Solution :* First, determine conductivity cell constant `(G^(**))`. By using this cell MEASURE the resistance and IONIC conductivity of any solution. * (A) MEASUREMENT of resistance of solution : The set up for the measurement of the resistance is shown in the FIGURE below:  * It consists of two RESISTANCES `R_(3) and R_(4)`, a variable resistance `R_(1)` and the conductivity cell having the unknown resistance `R_(2)`. the Wheatstone bridge is fed by an oscillator O (a source of a.c. power in the audio frequency range 550 to 5000 cycles per second). * P is a suitable detector (a headphone or other electronic device) and the bridge is balanced when no current passes through the detector. * (B) Calculation for resistance of solution : In this condition, unknown resistance of unknown solution is obtained by following formula: `(R_(2)=(R_(1)R_(4))/(R_(3))=R)` * These days, inexpensive conductivity meters are available. * Electric resistance R is measured in ohm which has `Omega` symbol. `(R=rho((l)/(A))=(1)/(kappa)((l)/(A))=(G^(**))/(kappa))` Where, R=Resistance `G^(**)`=Cell constant=`G^(**)=(l)/(A)` `rho`=Resistivity `kappa` (kappa)=Conductivity of solution. |
|