Question

At infinite dilution equivalent conductances of \(Ba^{2+}\) & \(Cl^–\) ions are  \(127\)  & \(76\) \(ohm^{–1}cm^{–1}eq^{–1}\) respectively. Equivalent conductance of \(BaCl_2\) at infinite dilutions is:

• A. 139.5
• B. 101.5
• C. 203
• D. 279

Answer 1

The Correct Option is A

To find the equivalent conductance of \( BaCl_2 \) at infinite dilution, we use the concept of Kohlrausch's Law, which states that the molar conductance of an electrolyte at infinite dilution equals the sum of the molar conductances of its individual ions.

According to Kohlrausch's Law, the equivalent conductance at infinite dilution for \( BaCl_2 \) can be calculated as follows:

The equivalent conductance of \( BaCl_2 \):

1. The formula for calculating the equivalent conductance at infinite dilution is given by: \[ \lambda_{eq}^\infty(\text{BaCl}_2) = \lambda_{eq}^\infty(\text{Ba}^{2+}) + 2 \times \lambda_{eq}^\infty (\text{Cl}^-) \]
2. Substituting the given values:
   • \(\lambda_{eq}^\infty (\text{Ba}^{2+}) = 127 \, \text{ohm}^{-1} \, \text{cm}^2 \, \text{eq}^{-1}\)
   • \(\lambda_{eq}^\infty (\text{Cl}^-) = 76 \, \text{ohm}^{-1} \, \text{cm}^2 \, \text{eq}^{-1}\)
3. Calculate: \[ \lambda_{eq}^\infty (\text{BaCl}_2) = 127 + 2 \times 76 \] \[ = 127 + 152 \] \[ = 279 \, \text{ohm}^{-1} \, \text{cm}^2 \, \text{eq}^{-1} \]

From the given options, 279 is not listed; however, an error or different interpretation might lead to the issue in the options provided. With the common data and interpretation, the above calculations should be correct.