The correct option is
C ![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1201671/original_1.png)
Variation in molar conductivity of strong electrolyte due to ion-ion interaction is given by an empirical relation proposed by kohlrausch.
Λm=Λ0m−A√C
Λm - Molar conductivity
Λ0m - Limiting molar conductivity
C is concentration of electrolyte
A is constant for a given solvent and temperature.
Λm=Λ0m−A√C
This equation is in the form of straight line equation,
y=c+mx
∴
Plot of
Λm vs √C
Intercept :
Λ0m
Slope :
−A
All electrolytes of a particular type have the same value for ‘A’.
Since
KCl and
NaCl are of same type (equal charge on cation and anion), they have similar
A value which means they have a same slope. So, their will be of parallel to each other.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1201679/original_1.png)
Thus, graph (c) is incorrect.
KCl and
MgSO4 is of different type of electrolyte, charges on cations and anions are ,
KCl ⇒+1,−1MgSO4 ⇒+2,−2
So they have different slope hence, they dont have a parallel lines.
Thus, graph (b) is incorrect.
In graph (d), we have
CH3COOH which is a weak electrolyte. Weak electrolyte will have a rectangular parabola curve and it does not intercept the y-axis.
Thus, graph (d) is also incorrect.
Hence, graph (a) is the correct one.