问题
单项选择题
用硝酸银滴定法，以铬酸钾作指示剂，测水中氯化物时，水样pH的范围应是（）
A.pH7～10
B.pH2～4
C.pH12以上
D.pH10～12
E.pH4～6
答案
参考答案：A
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用硝酸银滴定法，以铬酸钾作指示剂，测水中氯化物时，水样pH的范围应是（）
A.pH7～10
B.pH2～4
C.pH12以上
D.pH10～12
E.pH4～6
参考答案：A
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Amanda is a very kind girl. She is always 1 to help peo ple who are in trouble. Now Amanda is 2 in the University of Texas. At the same time, she is volunteering to teach at Heart House in her 3 time. Heart House is a local after-school program for children. It 4 some extra education for those children who are not doing well in their studies. Amanda goes to Heart House to teach the children twice a week. She has also 5 a website for Heart House. In this way, more people will have more chances to learn about Heart House and 6 the children there. Because of Amanda's website, every week 125 volunteers 7 about four hours helping the children at Heart House now. "Without Amanda's website, Heart House would be 8 to have enough volunteers. Her support is much appreciated," the program leader says. "I feel happy to teach those kids how to study. The 9 thing is that I can also learn a lot from them, too. I won't give up volunteering after graduation. I hope to 10 teaching kids who need help," Amanda says. |