问题 选择题

常温下,将Cl2缓慢通入一定量的水中至饱和,然后向所得饱和氯水中逐滴加入0.1mol·L-1的氢氧化钠溶液,整个过程中pH变化如图所示,下列有关叙述正确的是

A.②点之前所发生反应的离子方程式为Cl2+H2O=2H++Cl+ClO

B.③点所示溶液中:c(Na+)= c(HClO)+2c(ClO-)

C.实验进程中溶液的pH可以用pH试纸测得

D.曲线的起始点水的电离程度最大

答案

答案:B

题目分析:A、②点之前所发生Cl2与H2O反应生成HCl和HClO的反应,HClO为弱酸,不能拆成离子,错误;B、③点溶液呈中性,则c(H+)=c(OH-),根据电荷守恒得c(H+)+c(Na+)=c(Cl-)+c(Cl0-)+c(OH-),所以c(Na+)=c(Cl-)+c(ClO-),根据物料守恒得c(Cl-)=c(ClO-)+c(HClO),所以c(Na+)=c(HClO)+2c(ClO-),正确;C、因为氯水中含有HClO,具有漂白性,所以实验进程中溶液的pH不能用pH试纸测得,错误;D、Cl2与NaOH恰好反应时水的电离程度最大,错误。2的性质、图像的分析、pH试纸的使用、离子浓度比较、水的电离。

单项选择题
阅读理解

第三部分:阅读理解(共16小题;每小题2分,满分32分)

阅读下列短文,从每题所给的A、B、C、D四个选项中,选出最佳选项。

A

In recent years, advances in medical technology have made it possible for people to live longer than in the past. New medicine and machines are being developed every day to extend life. However, some people, including some doctors, are not in favor of these life extending measures, and they argue that people should have the right to die when they want. They say that the quality of life is as important as life itself, and that people should not be forced to go on living when the conditions of life have

become unbearable. They say that people should be allowed to die with dignity (尊严) and to decide when they want to die. Others argue that life under any conditions is always to extend life as long as possible. And the battle goes on and on without a definite (明确的) answer.

57. The best title for the passage is ______.

A. The Right to Live                     B. The Right to Die

C. The Doctor's Duty                     D. Death or Life

58. In recent years, people can live longer than in the past because of______.

A. the development of medical technology     B. big hospitals

C. good medical workers                  D. both B and C

59. In the eyes of the law, whether a dying patient has the right to die or not is up to ______.

A. the doctors                          B. the surroundings

C. the family                           D, the patient himself/herself

60. According to the writer's opinion ______.

A. death is better than life            B. life is better than death

C. neither death nor life is good       D. none of the above