Boric acid is heated to 100 ℃, due to constantly lose water, become metaborate it first, it has three variants, melting point 176 ℃, 201 ℃ and 236 ℃ respectively. Boric acid dehydration to produce metaborate ended (as long as the temperature does not exceed 150 ℃). After further heating, the water is stripped to form boron oxide. Crystal boron oxide melt when 450 ° C. The amorphous boron oxide has no definite melting point, it begins to soften, in 325 ℃ 500 ℃ all become liquid. Boric acid is a stable crystal, usually preserved without chemical reaction. Recrystallization and agglomeration occur when temperature and humidity fluctuate. When storing, keep away from drastic environment and keep the packaging intact.
We can also assume that boric acid
boron is already trivalent, it can no longer be oxidized, so it won't burn. But it produces a harmful combustion product: boron oxide.
Boric acid reacts with ethanol to form ester. H3BO3+3C2H5OH==(concentrated H2SO4, ignition)==B(OC2H5)3+3H2O, boric acid energy and alcohol form boric acid ester, boric acid ester combustion is green flame, can be used for boric acid qualitative analysis, but cannot be used for ethanol qualitative analysis.