问题 选择题

常温下,有下列四种溶液:

0.1mol/L NaOH溶液pH =" 11" NaOH溶液0.1mol/L CH3COOH溶液pH =" 3" CH3COOH溶液
 

下列说法正确的是 (  )

A.由水电离出的c(H+):①>③   

B.③稀释到原来的100倍后,pH与④相同

C.②与④混合,若溶液显酸性,则所得溶液中离子浓度可能为:

c(CH3COO-)>c(H+)>c(Na+)>c(OH-)

D.①与③混合,若溶液pH = 7,则V(NaOH)>V(CH3COOH)

答案

答案:C

题目分析:A、0.1mol/LNaOH溶液中,由水电离出的c(H+)为10-13mol/L,0.1mol/L CH3COOH溶液,c(H+)<0.1mol/L,则由水电离出的c(H+)大于10-13mol/L,所以由水电离出的c(H+)为①<③,错误;B、0.1mol/L CH3COOH溶液,c(H+)<0.1mol/L,则pH>1,可能为3,稀释100倍,pH增大,则③与④的pH大小无法确定,错误;C、②与④混合,若溶液显酸性,则为醋酸钠与醋酸的混合溶液,醋酸电离大于醋酸根离子水解,若醋酸较多,则c(H+)>c(Na+),结合电荷守恒可知溶液中离子浓度可能为c(CH3COO-)>c(H+)>c(Na+)>c(OH-),正确;D、①与③混合,若溶液pH=7,c(H+)=c(OH-),由电荷守恒可知c(CH3COO-)=c(Na+),则为醋酸和醋酸钠的混合液,醋酸浓度大于NaOH溶液的浓度,满足醋酸过量即可,所以V(NaOH)≤V(CH3COOH),或V(NaOH)>V(CH3COOH)也可能,错误。

单项选择题 A1/A2型题
单项选择题

Many in the Middle East have difficulty in adjusting themselves to the new situation created by the departure of the imperial powers. For the first time in almost 200 years, the rulers and people of the Middle East have to accept the final responsibility for their own affairs, to make their own mistakes and to accept the consequences. This is difficult to internalize, even to perceive, after so long a period. For the entire lifetimes of those who formulate and conduct policy at the present time and of their predecessors for many generations, vital decisions were made elsewhere, ultimate control lay elsewhere, and the principal task of statesmanship and diplomacy was as far as possible to avoid or reduce the dangers of this situation and to exploit such opportunities as it might from time to time offer. It is very difficult to forsake the habits not just of a lifetime but of a whole era of history. The difficulty is much greater when alien cultural, social and economic preeminence continues and even increases, despite the ending of alien political and military domination.

Military and to a growing extent political intervention by the West has indeed ended, but the impact of its science and culture, its technology, amenities and institutions remains and even increases. As in other parts of the non-Western world, this impact has been and will be enormous. In these circumstances, it is natural that Middle Easterners should continue to assume—and proceed on the assumption—that real responsibility and decision still lie elsewhere. In its crudest form, this belief leads to wild and strange conspiracy theories directed against those whom they regard as their enemies—Israel, and more generally the Jews, the United States, and more generally the West. No theory is too absurd to be asserted or too preposterous to be widely and instantly believed. Even among more responsible statesmen and analysts, a similar belief in alien power, albeit in a less crude form, often seems to guide both analysis and policy. Some even go so far as to invite outside intervention, presumable in the belief that only outside powers have the capacity to make and enforce decisions. A case in point is the constant appeal to the United States to involve itself in the Arab Israel conflict, oddly coupled with the repeated accusation of "American imperialism. "

This state of mind is likely to continue for some time, with appeals for support or even intervention to the United States, to Russia and even to the European Union. In time, no doubt, Middle Eastern governments and people will learn how to use this window of opportunity to the best advantage—that is, of course, if the window remains open long enough.

The author implied in the passage that()

A. it takes time for the Middle Easterners to adjust themselves to the new situation

B.the world will be more peaceful if each country learns to care about its own business

C. most of the unrest in the Middle East is attributable to Israel’s aggressive policies

D. the Western powers should stop interfering with other countries’ affairs