TO VERIFY UNSAGER'S EQUATION AND TO DETERMINE THE EQUIVALENT CONDUCTANCE OF NACI AT INFINITE DILUTION

 APPARATUS REQUIRED

• Volumetric flasks

• Beakers

• Conductumeter

• Conductivity Cell

• Measuring cylinder 

• Pipette 

CHEMICALS REQUIRED

• 0.2N Nacl soln in conductivity water.

THEORY

Debye Huckel Onsager's equation relates the variation of equivalent conductance of a strong electrolyte with its concentration. For a strong electrolyte, the equation is given as follows;

λ= [A+B λ°]√c

where, λ= eq.conductance at C concentration

λ = eq. conductance at infinite dilution.

A & B are constants

The equivalent conductance at C concentration is

given by

λ= (K×1000÷c)               [k = sp. conductance]

To verify the law, λ vorses √c is plotted in graph 8 by extraplotation of linear curve, λ° is determined.

PROCEDURE

The instrument was caliberated first & cell constant was noted. 0.001, 0.005, 0.01, 0.02, 0.05 & 0.1N NaCl solutions were prepared in 100 ml flack by dilution of 0.2N NaCl stock Solution. The conductances of each solutions were observed from using the conductivity cell. The specific equivalent conductances were calculated & graph between λ 8 √C was plotted.

RESULT 

From the graph the equivalent conductance at infinite dilution was found to be 3.

CONCLUSION

The Onsager's equation can be verified
and the equivalent conductance of NaCl at infinite dilution can be determined