查阅资料发现，硫酸铜溶液是过氧化氢分解反应的催化剂．为了验证该信息并进一步探究硫酸铜溶液中起催化作用的粒子，小明进行了如下分析及实验．

                                                                         My School Day in London
      Tim Hunt is telling 1 Chinese classmates about his school day in London.
     My school day in London is different 2 my school day here in China. School starts 3 nine o'clock. I get up at 7:00 4weekdays. I go to school 5 underground(地铁). It 6 about forty–five minutes. I have 7 at school. Classes are over at 3:15. It is early, 8 I stay at school and play games 9 my friends. I am 10 the basketball team. We practice(联系)on Monday 11 Wednesday. We have a match 12 Friday afternoon.
     On Saturday 13 I get up late. Then I 14 my parents tidy(弄整洁)the house and the garden. In the evening I often go to film or a club(俱乐部).On Sunday I have a good rest and of course, I do 15.

氢氧化钠溶液应保存在 ____（填“广口瓶”或“细口瓶”）中，在点燃氢气前要 ____；用洒精灯加热时，用的是 （填“焰心”或“外焰”），检验未知溶液中是否含有硫酸根离子选用的试剂是：BaCl₂ 和（填化学式），从碘水中提取碘的方法是： ____（填分液”、“蒸发”、“萃取”或“蒸馏”）．