an experiment was carried out for the polycondensation of ethylene glycol and adipic acid .at at time 20 minute intervals the volume needed to neutralise the polmer obtained was noted with the mass of the polymer obtained .

time volume, ml (koh) mass

20 7 0. 21g

40 9 0. 25g

60 12 0.29g

calculate acid value before the reaction ,the number average molar mass and number average degree of polymerisation using the obtained Acid value