MOH和ROH两种一元碱的稀溶液，分别加水稀释时pH变化可近似看作如图所示，下列说法错误的是（ ）
A．ROH是一种强碱
B．稀释前，c（ROH）＜10c（MOH）
C．在x点，ROH完全电离
D．在x点，c（M+）＜c（R+）
A．由图可知，ROH的pH=13时稀释100倍，pH变为11，则ROH为强碱，故A正确；
B．ROH为强碱，稀释前浓度为0.1mol/L，MOH的pH=12时稀释100倍，pH变为11，则说明MOH为弱碱，稀释前MOH的浓度大于0.01mol/L，则稀释前c（ROH）＜10c（MOH），故B正确；
C．ROH为强碱，则在x点，ROH完全电离，故C正确；
D．在X点，pH相同，则c（OH-）相同，由电荷守恒可知，c（M+）=c（R+），故D错误；
故选D．
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| In the United States, sixteen, eighteen, and twenty-one are important ages in a person's life. There are no special celebrations for these birthdays, but each is a time when a person can do new things to mark their transition (转变) into adult-hood (成人时期). After turning sixteen a person can work, get a driver's licence and leave home. Many high school students learn to drive and get part-time jobs soon after celebrating their sixteenth birthday. At the age of eighteen a person in the United States can vote and smoke, but they are prohibited from going into many nightclubs, buying wine or gambling (赌博) until they are twenty-one. In many Latin (拉丁的) cultures, a young woman's fifteenth birthday is important. At this age, she is regarded as an adult. To mark this special day, families with teenage daughters have a celebration called a Quinceanera. The day begins with the young woman and her family going to church. Later, there is a party and many guests are invited. In Japan, young people become adults at twenty. At this age, they can legally (合法的) vote, drink wine and smoke. The second Monday in January is a national holiday called Coming of Age Day. On this day, twenty-year-olds celebrate by first going to a church to pray with their families. Later, they listen to speeches given by city and school leaders. Afterward, many celebrate with family or friends late into the night. In some countries, birthday celebrations continue through adulthood. Some people celebrate their fortieth and fiftieth birthdays, or their retirement (退休) year, with a huge party. |
| 1. In the United States, age sixteen marks the time when you can ______. |
[ ] |
| A. vote and drive B. drive and get a job C. drink wine and smoke D. go into nightclubs |
| 2. In some Latin cultures, the fifteenth birthday is important for ______. |
[ ] |
| A. parents B. young men C. both young women and young men D. young women |
| 3. In Japan, young people are considered adults at age ______. |
[ ] |
| A. sixteen B. eighteen C. twenty D. twenty-one |
| 4. Which of the following is not the turning point in a person's life in the USA? |
[ ] |
| A. The 15th birthday. B. The 16th birthday. C. The 18th birthday. D. The 21st birthday. |
| 5. What is the meaning of the word "prohibit"? |
[ ] |
| A. 允许 B. 禁止 C. 终止 D. 支持 |