（12分）常温下，向100 mL 0.01 mol·L－1HA溶液中逐滴加入0_爱下问搜题

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问题填空题

（12分）常温下，向100 mL 0.01 mol·L^－1HA溶液中逐滴加入0.02 mol·L^－1MOH溶液，图中所示曲线表示混合溶液的pH变化情况(体积变化忽略不计)。回答下列问题：

(1)由图中信息可知HA为________酸(填“强”或“弱”)，理由是____________（2分）

(2)常温下一定浓度的MA稀溶液的pH＝a，则a________7(填“>”、“<”或“＝”)，用离子方程式表示其原因为__________________________；,此时，溶液中由水电离出的c(OH^－)＝________。（4分）

(3)请写出K点所对应的溶液中离子浓度的大小关系：__________ （2分）

(4)K点对应的溶液中，c(M^＋)＋c(MOH)________2c(A^－)(填“>”、“<”或“＝”)；若此时溶液中，pH＝10，则c(MOH)＋c(OH^－)＝________mol·L^－1。（4分）

答案

(1)强　0.01 mol·L^－1HA的pH为2，说明HA完全电离

(2)<　M^＋＋H₂OMOH＋H^＋,1×10^－amol·L^－1,(3)c(M^＋)>c(A^－)>c(OH^－)>c(H^＋),(4)＝　0.005

此题为关于溶解度曲线的题目，首先要看清曲线：起点（强酸弱酸、强碱弱碱），曲线平滑、滴定终点、pH=7的点等等。（1）因为浓度0.01mol/L,pH=2，故该酸为一元强酸；（2）V=50ml滴定终点时，pH<7，为强酸弱碱盐，水解为酸性。故该碱为弱碱，M⁺+H₂OMOH+H⁺，促进水的电离c(OH^－)＝1×10^－^amol·L^－¹；（3）K点为MA和MOH的混合溶液，故离子浓度大小关系为c(M^＋)>c(A^－)>c(OH^－)>c(H^＋)，（4）根据物料守恒，c(A-)+c(HA)=0.1L×0.01mol/L=0.001mol,c(M^＋)＋c(MOH)= 0.1L×0.02mol/L=0.002mol；故有c(M^＋)＋c(MOH)=2[c(A-)+c(HA)]> 2c(A-)

完形填空

James sat outside the office waiting for the interview. He felt so 36 that he didn’t know what to do with himself. The person who had gone in 37 him had been in there for nearly an hour. And she looked so confident when she went in, not like James. He felt 38 that she had already got the job. The problem was that he wanted his job so much. It meant everything to him. He had 39 it such a lot before the day of the interview. He had imagined himself 40 brilliantly（出色地）at the interview and being offered the job immediately. But now here he was feeling 41 . He couldn’t remember all those things he 42 to say. At that moment, he almost decided to get up and leave. But no – he had to do this. He had spent so much time considering it that he couldn’t 43 like that. His hands were hot and sticky and his mouth felt dry. At last the door of the office opened. The woman who had gone in an hour earlier came out looking very 44 with herself. She smiled sympathetically （同情地）at James. At the moment, James 45 her. The managing director then appeared at the office door. “would you like to come in now, Mr. Davis? I’m sorry to have kept you 46 .” James suddenly wished that he had gone home after all. He got up, legs 47 and forehead sweating and wondered he looked as terrified as he felt.

C．thought about

D．talked about

A．had planned

B．has planned

C．being waiting

单项选择题

根据《建设工程安全生产管理条例》规定，公路施工企业施工单位对因建设工程可能造成损害的毗邻建筑物、构筑物和地下管线等，应当采取（）

A.施工组织设计

B.施工方案

C.安全技术措施

D.专项防护措施