第13题: [单项选择]下列化学品中,不属于硝化剂的是( )。 A. 浓硝酸 B. 浓硝酸和浓硫酸配制的混合酸 C. 硝酸盐 D. 过氧化苯甲酰 参考答案:D 答案解析:硝化过程常用的硝化剂是浓硝酸或浓硝酸和浓硫酸配制的混合酸。此外,硝酸盐和氧化氮也可做硝化剂。一般的硝化反应是先把硝酸和硫酸配制成混酸,然后在严格控制温度的条件下将混酸滴人反应器,进行硝化反应。
第29题: [单项选择]Questions 23 to 25 are based on the conversation you have just heard. A. He lives on the 10th floor of Butler Hall. B. He never wants to listen to students. C. He used to teach biology. D. He is an excellent professor. 参考答案:D 答案解析:[听力原文] What does the man think about Professor Robert