Looking for classes? Ksquare Career Institute, Bengaluru →
Molar conductance of an electrolyte increase with dilution according to the equation: $\Lambda_m=\Lambda_m^\circ-A\sqrt{c}$. Which of the following statements are true? (A) This equation applies to both strong and weak electrolytes. (B) Value of the constant A depends upon the nature of the solvent. (C) Value of constant A is same for both $BaCl_2$ and $MgSO_4$. (D) Value of constant A is same for both $BaCl_2$ and $Mg(OH)_2$. Choose the most appropriate answer from the options given below:
A
(A) and (B) only
B
(A), (B) and (C) only
C
(B) and (C) only
D
(B) and (D) only
Detailed Solution
The Debye-Hückel-Onsager equation ($\Lambda_m=\Lambda_m^\circ-A\sqrt{c}$) applies only to strong electrolytes, not weak ones (A is false). The constant A depends on the nature of the solvent and temperature, and also on the valence type (charge type) of the electrolyte — so it is the same for electrolytes of the same charge type, like $BaCl_2$ and $Mg(OH)_2$ (both 2:1 type), but not necessarily the same for $BaCl_2$ (2:1 type) and $MgSO_4$ (2:2 type). So B and D are correct.