Phosgene, whose structure is represented below, is a highly toxic substance
and was used as a chemical weapon in World War I. He is also a
synthetic precursor used in the production of many plastics. When phosgene is
treated with ethylene glycol (HO-CH2CH2-OH), substance A (C3H4O3) is obtained.
Draw the structure of substance A and the complete mechanism for obtaining it a.
from the reaction of phosgene and ethylene glycol.