题目

阅读短文，回答问题The Middleton Fire Department received a call at 9: 30 on Friday night. The firemen were told that a house was on fire in Idaho. The firemen set off at once. When they arrived, they heard cries of helpandfire. They expected to find an elderly woman inside the house.However, after they went into the room and searched the house carefully, they couldn't find anyone. The cries continued （热成像技术）. However, it detected（探测）, but two parrots sitting on a table. One was talking, while the other seemed much quieter. In the end（营救） by the firemen su（1）已知锌与稀硫酸反应为放热反应，某学生为了探究其反应过程中的速率变化，用排水集气法收集反应放出的氢气，实验记录如下 ①反应速率最大的时间段(即0～1、l～2、2～3、3～4、4～5 min)为_____________， 原因是_______________________________________②反应速率最小的时间段为_________，原因是___________________________（2）另一学生也做同样的实验，由于反应太快，测量氢气的体积时不好控制，他就事先在硫酸溶液中分别加入等体积的下列溶液以减慢反应速率 A．蒸馏水 B．CuCl2溶液 C．NaCl溶液你认为他上述做法中可行的是__________________(填相应字母)；做法中不可行的理由是_______________________________