2011年5月初，我市某县一副长酒后驾车将受到法律追究。交警常用一种“酒精检测仪”检查司机是否酒后驾车。其反应原理为C2H5OH + 4CrO3 + 6H2SO4 =" 2X" + 2CO2↑+9H2O,反应中红色的CrO3转化为绿色的化合物X，则X的化学式为（ ）
I have a pencil box. It's blue. There are lots of things in it. I have a pen. It's red and long. I like it. I have three pencils. They are short. I have a ruler. It's big. I have an eraser. It's small.
