问题 选择题

25 ℃时,0.1 mol/L的HA溶液中c(H)/c(OH)=l×l06,下列叙述正确的是

A.该溶液中由水电离出的c(H)=l×1013 mol/L

B.由pH=4的HA与pH=10的NaOH溶液等体积混合,溶液中c(Na)>c(A)>c(OH)>c(H)

C. 浓度均为0.1 mol/L的HA和NaA溶液等体积混合,若溶液呈酸性,则c(A)>c(HA)>c(Na)>c(H)>c(OH

D.0.1 mol·L1 HA溶液与0.05 mol·L1 NaOH溶液等体积混合后所得溶液中c(H)+c(Na)=c(OH)+c(A)

答案

D 

c(H)/c(OH)=l×106,则c(H)=l×104 mol/L,c(OH)=l×1010 mol/L,由此可知HA为弱酸,水电离出的c(H)=c(OH)=1×1010 mol/L,A项错误;由pH=4的HA与pH=10的NaOH溶液等体积混合后溶液呈酸性,B项错误;浓度均为0.1 mol/L的HA和NaA溶液等体积混合,若溶液呈酸性,说明溶液中HA的电离大于A离子的水解,溶液中c(Na)>c(HA),C项错误;根据溶液的电中性可知溶液中存在c(H)+c(Na)=c(OH)+c(A),D项正确。

完形填空
完形填空
The Smiths are taking a vacation next week. At first, they thought about   1    to Beijing. Because they went there three times, so there’s nothing  2 for them. This time, they want to go  3 .   4 are they going then? “I want to go to Jiuzhaigou,” said Tom. “But it’s quite  5  from here and we have only two,” Mary disagreed. “I think we should go somewhere near here.” And  7 they decided  8  to Qingdao. Qingdao is famous     9   its beautiful beaches.
They are leaving  10 Friday evening and staying there   11  two days. On the first day, they are going to the  12  to see the dolphins(海豚). On the second day, they are going to the beach and    13   there. They are taking  14  on the beautiful beach. They are sure that they will  15  themselves in Qingdao.
小题1:
A.to goB.wentC.goingD.goes
小题2:
A.goodB.boringC.newD.old
小题3:
A.different somewhereB.different anywhere
C.anywhere differentD.somewhere different
小题4:
A.WhatB.WhereC.WhenD.How
小题5:
A.behindB.longC.farD.near
小题6:
A.weeksB.monthsC.yearsD.days
小题7:
A.lastB.firstC.at firstD.at last
小题8:
A.to goB.goingC.goD.went
小题9:
A.toB.aboutC.forD.at
小题10:
A.inB.onC.atD.to
小题11:
A.forB.inC.atD.on
小题12:
A.zooB.shopC.townD.cinema
小题13:
A.going swimming     B.going skating
C.playing tennis   D.playing baseball
小题14:
A.lessons B.photosC.soccerD.movie
小题15:
A.likeB.enjoyC.enterD.study
问答题