When in conferences, he often leaves for ____ (各种各样的) reasons.
某次酸雨的分析数据如下
NH4+=2.0×10﹣5mol/L,Cl﹣=6.0×10﹣5mol/L,Na+=1.9×10﹣5mol/L,
NO3﹣=2.3×10﹣5mol/L,SO42﹣=2.8×10﹣5mol/L,
其他微粒离子忽略不计,计算该雨水的pH为____ .