题目

下列各组物质，要借助酸碱指示剂才能判断反应发生的是（ ） A．石灰石与盐酸 B．Fe2O3+HCl C．Ba（OH）2+H2SO4   D．NaOH+HCl 答案：【考点】反应现象和本质的联系；酸碱指示剂及其性质；酸的化学性质． 【专题】常见的酸 酸的通性． 【分析】物质间的反应若有明显的反应现象，如产生沉淀或气体或固体溶解的现象，则不需要借助指示剂，如反应时没有明显现象的需要借助指示剂，特别是酸碱中和反应． 【解答】解：A、石灰石 Not only __________ interested in football but _________ beginning to show an interest in it. A. the teacher himself is, all his students are    B. the teacher himself is, are all his students   C. is the teacher himself, are all his students    D. is the teacher himself, all his students are