在环己烯制备实验中,用磷酸做脱水剂,比用浓硫酸做脱水剂有何优点?
参考答案:
磷酸氧化性小,有机物碳化少;浓硫酸还原后生成二氧化硫,气味难闻。
My grandparents like to live in a house is not very big but bright and comfortabe.
A. which B. who C. what
土地需求