acid酸揮發了什麼

This is because most inorganic acids such HCl , H2SO4 , HNO3 are respectively their gases dissolved in water . HCl is made from dissolve 35 % hydrogen chloride in water therefore concentrated HCl will has HCl gas coming out . Also when the acid is subjected to heat HCl gas will come out from the acid solution . So SO3 for sulphuric acid & NO2 for nitric acid .