5.
已知下列实验事实:
\(\rm{①Cr_{2}O_{3}}\)固体既能溶于\(\rm{KOH}\)溶液得到\(\rm{KCrO_{2}}\)溶液,又能溶于硫酸得到\(\rm{Cr_{2}(SO_{4})_{3}}\)溶液;
\(\rm{②}\)向\(\rm{KCrO_{2}}\)溶液中滴加\(\rm{H_{2}O_{2}}\)溶液,再酸化,可得\(\rm{K_{2}Cr_{2}O_{7}}\)溶液;
\(\rm{③}\)将\(\rm{K_{2}Cr_{2}O_{7}}\)溶液滴加到淀粉和\(\rm{KI}\)的混合溶液中,溶液变蓝.
下列判断不正确的是\(\rm{(}\) \(\rm{)}\)