At a certain temperature and at infinite dilution, the equivalent conductance of sodium benzoate, hydrochloric acid and sodium chloride are 240,349 and 229 $ohm^{-1} cm^2 equiv^{-1}$ respectively. The equivalent conductance of benzoic acid in $ohm^ {-1}\;cm^2\;equiv^{-1}$ at the same conditions is :

Question

$$\begin {array} {1 1} (1)\;80 & \quad (2)\;328 \\ (3)\;360 & \quad (4)\;408 \end {array}$$