第17题: [单项选择]下列各组溶液中具有缓冲作用的溶液是( )。 A. KOH溶液和KNO3溶液 B. 50mL0.5 mol/L的HCl溶液和25mL0.5 mol/L的NaOH溶液 C. 25mL0.5 mol/L的HAc溶液和50mL0.5 mol/L的NaOH溶液 D. 30mL0.1 mol/L的NH3·H2O溶液和20mL0.1 mol/L的HCl溶液 参考答案:D 答案解析:必须是弱酸与弱酸盐或者弱碱与弱碱盐组成的溶液才具有缓冲作用
A. Physical therapy equipment. B. Nuclear medicine room. C. A new operation room. D. A restaurant. 参考答案:C 答案解析:[听力原文] 11-13 I am glad you have all had the opportunity to come here today for the opening of