An analytical chemist weighs out of an unknown diprotic acid into a volumetric flask and dilutes to the mark with distilled water. She then titrates this solution with solution. When the titration reaches the equivalence point, the chemist finds she has added of solution. Calculate the molar mass of the unknown acid. Be sure your answer has the correct number of significant digits.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.