Question

What would be the equivalent conductivity of a cell in which $0.5\, N$ salt solution offers a resistance of $40 \,ohm$ whose electrodes are $2 \,cm$ apart and $5 \,cm^2$ in area?

• A. $10\,ohm^{-1}\,cm^{2}\,eq^{-1}$
• B. $20\,ohm^{-1}\,cm^{2}\,eq^{-1}$
• C. $30\,ohm^{-1}\,cm^{2}\,eq^{-1}$
• D. $25\,ohm^{-1}\,cm^{2}\,eq^{-1}$

Answer 1

Answer: (B)

$\kappa=\frac{1}{R}\times\frac{l}{A}=\frac{1}{40}\times\frac{2}{5}$
$\Lambda_{eq}=\kappa\times\frac{1000}{N}$
$=\frac{1}{40}\times\frac{2}{5}\times\frac{1000}{0.5}$
$=20\,ohm^{-1}\,cm^{2}\,eq^{-1}$