An experiment was undertaken to determine the effect of different liquids upon the swelling of a vulcanized sample of natural ru
bber at room temperature. It was found that the equilibrium swelling ratio of the natural rubber in carbon tetrachloride was 5.5 and in benzene it was 4.4. Given the information below determine the following parameters. (a) The molar mass between crosslinks, Mc for the natural rubber sample.
(b) The value of the Flory-Huggins interaction parameter, x, for natural rubber in benzene.
(The density of natural rubber=910 kg M^-3; Flory-Huggins interaction parameter x for natural rubber in carbon tetrachloride=0.290; molar volume of carbon tetrachloride=97.1 x 10^-6 m^3 mol^-1; and molar volume of benzene=89.4 x 10^-6 m^3 mol^-1.)
Its the other way around actually. Benzoic acid is stronger than acetic acid because the electron-donating inductive effect (+I) by the alkyl group on acetic acid destabilise the conjugate base of acetic acid.