Question

The ionic conductance of $B{a}^{2+}$ and $C{l}^{-}$ are respectively $127$ and $76oh{m}^{-1}c{m}^{2}mo{l}^{-1}$ at infinite dilution. The equivalent conductance (in $oh{m}^{-1}c{m}^{2}e{q}^{-1}$) of $BaC{l}_2$ at infinite dilution will be:

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

Answer 1

The correct option is B $139.5$

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 $=139.5oh{m}^{-1}c{m}^{2}e{q}^{-1}$

Hence, the correct option is $\text{B}$.