题目

室温下，VaLpH=a的强酸与VbLpH=b的强碱溶液混合，混合后溶液pH=3。已知a+b=13,Vb=4.5Va,则a值为                          A. 2           B. 3        C. 4        D. 5   答案：A解析: 补全对话。A:Hello! Jane speaking. 1. ______________B:This is Mrs Brown. You didn't come to school this morning. 2. ___________A:Sorry,I forgot to ask for leave. I feel terrible. I can't fall asleep these days. B:3. ______________ But how is that?A:I keep thinking about the coming exam. B:4. _______________________ I'm sure you can do it quite well. Try to relax yourself. Listen to some music or do some sports.A:5.____________________________B:I hope you will be better soon. Bye. A:Goodbye.