题目

                Answering the Community Needs of Our City     The Silver City Couneil recognizes thatcitizens have certain needs. To better meet your needs, we have made severalchanges to community facilities in 2004. This chart shows how we have triedto make your life better. Transport2Some hieileities at Station StreetHospital have been upgraded. Three stations for the suburt have beenadded to the western trato service. 20 new huses for the southern line werepurchased in January. 50 per cent of oir bus-stops have been upgraded. Busesto the eastern suburbs will run ever海水是巨大的资源宝库，从海水中提取食盐和溴的过程如下：（1）写出步骤I中生成低浓度Br2的离子方程式______。（2）步骤I中已获得Br2，步骤I中又将Br2还原为Br-，其目的为富集溴元素，请写出步骤II的化学方程式_______。（3）在3mL溴水中加入1mL四氯化碳，振荡、静置后，观察到试管里的分层现象为如图中的_______。（4）某化学研究性学习小组为了解从工业溴中提纯溴的方法，查阅了有关资料：Br2的沸点为59℃，微溶于水，有毒性和强腐蚀性，他们设计了如图装置简图。请你参与分析讨论：①C中液体产物颜色为_____。②用离子方程式解释NaOH浓溶液的作用______。