化学高手进来下～

sunsilk_cv

What is the pH of a solution that is 0.30M in HCOOH and 0.52M in HCOOK?


答案是写4.01,但是我不懂怎样做到3.53 chemistry很不dim啊～
救命下～HCOOH的Ka value是不是1.7x10^-4?

sunsilk_cv

可怜0回复

sookchin

HCOOH is weak acid,HCOOK is salt of HCOO-
the solution is buffer..
if want to find pH,jz substitute formula
    pH= -log Ka-log(conc of acid/conc of salt)
        = -log 1.74^-4  - log ( 0.3/0.52)
        =4.008
        = 4.1

sunsilk_cv

回复 3# sookchin


   
娃哈哈！谢谢你～知道我哪里错了～粗心啊！con. base 和con.acid倒转了