When rendering <chem>C2H5OH{} + C2H5OH ->[\ce{cc.\ H2SO4}] C2H5-O-C2H5{} + H2O</chem> in Chrome Version 70.0.3538.77(64) it gets cut off at the top (see below)
Bug reported here: https://hu.wikipedia.org/wiki/Szerkeszt%C5%91vita:Debenben#Dietil-%C3%A9ter