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WBJEE · Chemistry · Electrochemistry

The molar conductances of \(\mathrm{Ba}(\mathrm{OH})_2, \mathrm{BaCl}_2\) and \(\mathrm{NH}_4 \mathrm{Cl}\) at infinite dilution are \(523.28,280.0\) and \(129.8 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}\) respectively. The molar conductance of \(\mathrm{NH}_4 \mathrm{OH}\) at infinite dilution will be

  1. A \(125.72 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}\)
  2. B \(251.44 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}\)
  3. C \(502.88 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}\)
  4. D \(754.32 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(251.44 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}\)

Step-by-step Solution

Detailed explanation

\begin{aligned} 2 \lambda_{\mathrm{m}\left[\mathrm{NH} \mathrm{H}_4 \mathrm{OH}\right]}^{\infty} & =2 \lambda_{\mathrm{m}[\mathrm{NH} 4 \mathrm{Cl}]}^{\infty}-\lambda_{\mathrm{m}\left[\mathrm{BaCl}_2\right]}^{\infty}+\lambda_{\mathrm{m}\left[\mathrm{Ba}(\mathrm{OH})_2\right]}^{\i…