Question

The ionic conductance of $B{a}^{2+}$ and $C{l}^{-}$ respectively are $127$ and $76{\Omega }^{-1}c{m}^2$ at infinite dilution. The equivalent conductance of $BaC{l}_2$ at infinite dilution will be

• A. $330{\Omega }^{-1}c{m}^2$
• B. $203{\Omega }^{-1}c{m}^2$
• C. $139{\Omega }^{-1}c{m}^2$
• D. $51{\Omega }^{-1}c{m}^2$

Answer 1

Answer: (C)

Equivalent conductance is defined as conducting power of all the ions produced by one gram equivalent of electrolyte.
The equivalent weight of
$BaC{l}_2=\frac{\text{ molecular weight }}{2}$
${\lambda }_m^{\infty }$ for $BaC{l}_2={\lambda }_{m\left(B{a}^2\right)}^{\infty }+2{\lambda }_{m\left(C{l}^{-}\right)}^{\infty }$
$\therefore {\lambda }_{eq}^{\infty }$ for $BaC{l}_2=\frac{1}{2}{\lambda }_{m\left(B{a}^{2-}\right)}^{\infty }+{\lambda }_{m\left(C{l}^{-}\right)}^{\infty }$
$=\frac{127}{2}+76$
$=139.5oh{m}^{-1}c{m}^{2}e{q}^{-1}$
The correct answer is $=139.5oh{m}^{-1}c{m}^{2}e{q}^{-1}$