1. Edited my statement ... the percentage I have  given are examples.. Organic compounds (rubber/plactics) that are reactive with ethanol will react with ethanol no matter the amount used. Chemical reaction is based on 1. strenght of reaction of the compounds. 2. present of compounds.. decreasing one particular compound decrease chance of compounds in contact with each other that triggers reaction. Therefore chemical reaction may last days/months/years until an equilibrium is reached.

2. Heat transfer (fizik) has a direct correlation with heat capasitance (Energy needed to increase one Kelvin) of the liquid phase, vanderWaals energy, molecular vibration, molecular movement and so on. Boiling point is where the liquid has reach its maximum heat storage ability and additional heat is transfered to the phase change to gaseous molecules.

3. Pure H2O has a much higher corrosive ability than ethanol... It is the measurement of the ability of the  H+, proton to disassociate from the molecule for reaction.