Question

The molar conductance of KCl, HCl and \( \text{CH}_3 \text{COOK} \) are 152, 425 and 91 cm\(^2\) ohm\(^-1\) respectively. Here, the molar conductance of \( \text{CH}_3 \text{COOH} \) at infinite dilution would be.

• A. 346 cm\(^2\) ohm\(^{-1}\)
• B. 364 cm\(^2\) ohm\(^{-1}\)
• C. 389 cm\(^2\) ohm\(^{-1}\)
• D. 486 cm\(^2\) ohm\(^{-1}\)

Hint:

When calculating the molar conductance of a compound at infinite dilution, use the formula \( \lambda_m = \lambda_m(\text{solute 1}) + \lambda_m(\text{solute 2}) - \lambda_m(\text{solvent}) \).

Answer 1

The Correct Option is B

We are given the following molar conductance values:
- \( \lambda_m(\text{KCl}) = 152 \, \text{cm}^2 \, \text{ohm}^{-1} \)
- \( \lambda_m(\text{HCl}) = 425 \, \text{cm}^2 \, \text{ohm}^{-1} \)
- \( \lambda_m(\text{CH}_3 \text{COOK}) = 91 \, \text{cm}^2 \, \text{ohm}^{-1} \)
The molar conductance of \( \text{CH}_3 \text{COOH} \) at infinite dilution can be found using the relationship: \[ \lambda_m (\text{CH}_3 \text{COOH}) = \lambda_m (\text{CH}_3 \text{COOK}) + \lambda_m (\text{HCl}) - \lambda_m (\text{KCl}) \] Substituting the given values: \[ \lambda_m (\text{CH}_3 \text{COOH}) = 91 + 425 - 152 = 364 \, \text{cm}^2 \, \text{ohm}^{-1} \] Thus, the molar conductance of \( \text{CH}_3 \text{COOH} \) at infinite dilution is 364 cm\(^2\) ohm\(^{-1}\).