KEAM 2014 Physics and Chemistry Paper

The values of limiting ionic conductance of H+ and HCOO− ions are respectively 347 and 53 S mol−1 1 at 298 K. If the molar conductance of 0.025M methanoic acid at 298 K is 40 S cm2‌mol−1, the dissociation constant of methanoic acid at 298 K is