Given the following molar conductivities at \[{{250}^{o}}C;HCl,425\,{{\Omega }^{-1}}c{{m}^{2}}mo{{l}^{-1}};\]\[NaCl\,\,125{{\Omega }^{-1}}\]\[c{{m}^{2}}mo{{l}^{-1}}\]NaC (sodium crotonate), \[82\,{{\Omega }^{-1}}c{{m}^{2}}mo{{l}^{-1}};\] what is the ionisation constant of crotonic acid? If the conductivity of a 0.001 M crotonic acid solution is \[3.82\times {{10}^{-4}}{{\Omega }^{-1}}c{{m}^{-1}}\]?

• A. \[1.5\times {{10}^{-4}}\]
• B. \[1.11\times {{10}^{-5}}\]
• C. \[2.11\times {{10}^{-5}}\]
• D. \[1.8\times {{10}^{-5}}\]