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Gaokao Chemistry Practice Question

一些化学试剂久置后易发生化学变化。下列化学方程式可正确解释相应变化的是

  1. A.硫酸亚铁溶液出现棕黄色沉淀: $6 \mathrm{FeSO}_4 + \mathrm{O}_2 + 2 \mathrm{H}_2\mathrm{O} \rightarrow 2 \mathrm{Fe}_2(\mathrm{SO}_4)_3 + 2 \mathrm{Fe}(\mathrm{OH})_2 \downarrow$
  2. B.硫化钠溶液出现浑浊颜色变深: $\mathrm{Na}_2\mathrm{S} + 2\mathrm{O}_2 \rightarrow \mathrm{Na}_2\mathrm{SO}_4$
  3. C.溴水颜色逐渐褪去: $4\mathrm{Br}_2 + 4\mathrm{H}_2\mathrm{O} \rightarrow \mathrm{HBrO}_4 + 7\mathrm{HBr}$
  4. D.胆矾表面出现白色粉末: $\mathrm{CuSO}_4 \cdot 5\mathrm{H}_2\mathrm{O} \rightarrow \mathrm{CuSO}_4 + 5\mathrm{H}_2\mathrm{O}$

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