下列各组离子中，能在强酸性溶液里大量共存，并且溶液呈无色透明_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

下列各组离子中，能在强酸性溶液里大量共存，并且溶液呈无色透明的是（　　）

A．MnO₄^-、K⁺、Na⁺、SO₄^2-

B．Na⁺、K⁺、HCO₃^-、Cl^-

C．Mg²⁺、K⁺、C1^-、NO₃^-

D．Ba²⁺、K⁺、CO₃^2-、SO₄^2-

答案

A．MnO₄^-有颜色，与溶液无色不符，故A错误；

B．酸性条件下，HCO₃^-与H⁺反应生成气体而不能大量存在，故B错误；

C．四种离子无色，且在酸性条件下不发生任何反应，能大量共存，故C正确；

D．酸性条件下，HCO₃^-与H⁺反应生成气体而不能大量存在，并且SO₄^2-与Ba²⁺生成沉淀而不能大量存在，故D错误．

故选C．

听力题

小题1:Days and nights z___________ by and everything changed before my eyes.

小题2: After a hard day of work, the man arrived home and his face looked tired and w________.

小题3: Firefighters could use RealCine to train safely, without the risk of getting i_________.

小题4:In defeat, the Kangaroos found something more ____________（珍贵的）than victory.

小题5:It was said that he had been __________（允许）into Nanjing University.

小题6:Single women were allowed to take part in their own c___________ at a separate festival.

小题7:I have been invited to your school to talk to you about the s____________ of the Olympic games.

小题8: When the woman could not completed her long distance phone call, she called one of the _____________（操作人员）for help.

小题9: The woman ___________（起诉）of stealing in a grocery proved innocent at last.

小题10: He became captain of the Brazilian football team and scored the w_________ goal.

单项选择题

以杜威为代表所倡导的教育理论主张被称为

A．现代教育派
B．传统教育派
C．形式教育论
D．实质教育论