搜题请搜索小程序“爱下问搜题”
问题 选择题

用铂作电极电解一定浓度的下列物质的水溶液．电解结束后，向剩余电解液中加适量水，不能使溶液和电解前相同的是（　　）

A．AgNO3

B．H2SO4

C．NaOH

D．NaNO3

答案

A．电解，阴极生成Ag，阳极生成氧气，向剩余电解液中加适量水，不能使溶液和电解前相同，故A选；

B．电解H2SO4，两极生成的产物是氧气和氢气，相当于电解的水，加入水可使溶液和电解前相同，故B不选；

C．电解NaOH，两极生成的产物是氧气和氢气，相当于电解的水，加入水可使溶液和电解前相同，故C不选；

D．电解NaNO3，两极生成的产物是氧气和氢气，相当于电解的水，加入水可使溶液和电解前相同，故D不选．

故选A．

填空题

President Bush arrived in Washington and forged ahead with an ambitious agenda- (1) tax cuts, vast changes in federal social programs, expansions of executive power and (2) broad remaking of energy and education policies.
Claiming a mandate by simply declaring (3) existence, his early successes dazzled his critics. With guru Karl Rove directing the (4) , Bush won a stunning series of political victories.
He muscled his agenda through (5) friendly Congress, and gained seats for his party in the 2002 midterm elections. (6) biggest triumph came in 2004, when he won a second term despite a (7) unpopular war.
The "permanent" Republican majority he and Rove envisioned even seemed attainable (8) Bush plunged himself into his most ambitious legislative effort yet: a partial privatization (9) Social Security.
But the president who boasted about "political capital" in the heady (10) after his re-election now faces the worst of political fates as he enters (11) final year in office: borderline irrelevance.
The president’s second term has (12) defined by legislative paralysis, marked by record-low approval ratings, presidential candidates who are (13) from his shadow, and a lingering war that’s sapping his remaining reservoirs of (14) .
As he enters his final year in office with the war continuing, Republican (15) for president bolting from his shadow, and his party back in the minority (16) Congress, he is politically weakened, an early entry into lame-duck status.
And the (17) Washington atmosphere he hoped to cure is just as nasty as it was (18) he came to office seven years ago.
"lie’s left our political institutions much (19) troubled than they were before," said Thomas E. Mann, a senior fellow at (20) Brookings Institution, a Washington-based think tank. "He didn’t create the ideological polarization, but he magnified it. \
查看答案
问答题 简答题

交流接触器的构造主要包括哪几部分？
查看答案