题目

Waste tends to be the pollution problem _______ other problems are eventually reduced. A . of which B . to which C . by which D . through which 答案：B在一定条件下，反应2A(g)＋2B(g)3C(g)＋D(g)．达到平衡状态的标志是 [　　] A．单位时间内B，C的反应速率之比为2∶3 B．A的消耗速率与B的生成速率相等 C．A，B，C，D的浓度之比为2∶2∶3∶1 D．反应容器内的压强不随时间的变化而变化