4.
有关物质及其用途的描述,正确的是( )
\(\rm{①Al_{2}O_{3}(}\)作耐火坩埚\(\rm{)}\) \(\rm{②KAl(SO_{4})_{2}·12H_{2}O(}\)作水的消毒剂\(\rm{)}\) \(\rm{③Fe_{2}O_{3}(}\)作黄色油漆和涂料\(\rm{)}\) \(\rm{④NaHCO_{3}(}\)作食用碱\(\rm{)}\) \(\rm{⑤}\)钠、钾、锶、钡等化合物\(\rm{(}\)作烟花的焰色\(\rm{)}\)
\(\rm{⑥Na_{2}O_{2}(}\)作呼吸面具供氧剂\(\rm{)}\)