(1)
(2) B D (3)SO 2+2H 2O-2e -=SO 4 2-+4H +B A
2SO 2+O 2+2H 2O=2H 2SO 4(或2SO 2+O 2+2H 2O=4H ++2SO 4 2-)(4)5 Fe 2++MnO 4 -+8H +=5Fe 3++Mn 2++4H 2O
(5)滴定最后一滴酸性KMnO 4时溶液呈淡紫色,半分钟内不褪色。(6)0.975或97.5%
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(1)
(2) B D (3)SO 2+2H 2O-2e -=SO 4 2-+4H +B A
2SO 2+O 2+2H 2O=2H 2SO 4(或2SO 2+O 2+2H 2O=4H ++2SO 4 2-)(4)5 Fe 2++MnO 4 -+8H +=5Fe 3++Mn 2++4H 2O
(5)滴定最后一滴酸性KMnO 4时溶液呈淡紫色,半分钟内不褪色。(6)0.975或97.5%
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