问题 选择题

X是一种消毒杀菌效率高、污染小的水处理剂.制备原理为:2KClO3+4HCl(浓)=2KCl+2X+Cl2↑+2H2O

试根据质量守恒定律推断X的化学式为(  )

A.HClO3

B.HClO

C.Cl2O5

D.ClO2

答案

根据质量守恒定律和化学方程式可知,X的化学式中应含有K的个数为:(2-2)÷2=0,含有Cl的个数为:(2+4-2-2)÷2=1,含有O的个数为:(2×3-2)÷2=2,含有H的个数为:(4-2×2)÷2=0;故可推断X的化学式为:ClO2

故选D.

单项选择题

It was two years ago today that the hunting ban came into force, supposedly ending centuries of tradition. However, the law has been an unmitigated failure—not that either side is shouting about it.
It was a nightmare vision that struck fear and loathing into the hearts of millions. When the hunting ban became law, it was said, 16,000 people would lose their jobs, thousands of hounds would be put down, rotting carcasses would litter the countryside, hedgerows would disappear, riders would face on-the-spot fines, law-abiding people from doctors to barristers would be dragged from their horses and carted off to prison, while dog owners would be prosecuted if their mutt caught a rabbit.
These were just some of the claims as desperate countryside campaigners battled to save their sport in the lead—up to the hunting ban, which Labour rammed into law using the Parliament Act on November 18, 2004.
For many, the fears were real. Others exaggerated as they fought an increasingly aggressive anti-hunting lobby which had rejected acres of independent evidence affirming that hunting is the most humane way of killing foxes. In the battle to "fight prejudice, fight the ban", every emotive argument was deployed.
For its part, the anti-hunting brigade extravagantly claimed that the ban would put an end to the rich parading in red jackets. A senior Labour MP, Peter Bradley, admitted in this newspaper that it was, as many suspected, about "class war". He lost his seat shortly afterwards. But people in red coats did not disappear.
In fact, none of the forecasts came true. What did happen was something nobody had predicted: the spectacular revival and growth of hunting with hounds. In short, the hunting ban has been a failure.
Today, on the second anniversary of the ban’s coming into force on February 18, 2005, new figures show that participation in the sport has never been higher. It is so cheerful that two new packs have been formed, something that has not happened for centuries.
They include the seductively named Private Pack, set up by the financier Roddy Fleming in Gloucestershire. It operates on an invitation—only basis, a sort of hunting private members’ club. This can only mean one thing: like it or not, hunting is cool. Young people are taking it up, enticed by the element of rebellion and the mystique of what actually happens as hunts attempt to keep within the law.

The word "rebellion" underlined in the last Paragraph refers to ______.

A.betray

B.violation

C.department

D.contravention

单项选择题