②不稳定性 S2O4+H2O→S2O32+HSO3 S2O32+H+→S+SO2↑ SO32+H+→H2O+SO2↑ S2O32+2→S4O6 S2O32+C2→SO2 ③氧化性:H2SO4(浓)、K2S2O8② 不稳定性 S2O4 2-+H2O→S2O3 2-+HSO3 - S2O3 2-+H+→S↓+SO2↑ SO3 2-+H+→ H2O +SO2↑ S2O3 2-+I2→S4O6 2- S2O3 2-+Cl2→SO4 2- ③ 氧化性：H2SO4(浓)、K2S2O8