[化學] About titration question

看板TransBioChem作者 (take me away)時間13年前 (2012/06/30 01:54), 編輯推噓0(004)
留言4則, 1人參與, 最新討論串1/1
The titration of 100.0 mL of a 0.100 M solution of weak acid H3A with 0.200 M NaOH is carried out. What are the major species (except water) at each of the following specified points in the titration? A) HA2-, after 100.0 mL NaOH is added B) H2A- and HA2-, after 40.0 mL NaOH is added C) HA2- and A3-, after 120.0 mL NaOH is added D) HA2-, after 50.0 mL NaOH is added E) H2A- and HA2-, after 85.0 mL NaOH is added F) none of the above 我的問題是這樣子 H3A -> H2A- -> HA2- > A3- 0 50 ? ? 就是我不知怎麼算HA2-是100 A3-是150 希望有神手可以替我解答 感恩 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 111.248.12.130

06/30 14:47, , 1F
沒有Ka?
06/30 14:47, 1F

06/30 14:48, , 2F
沒有Ka的話會不太好判斷 到滴定終點大約是HA2- 之前是H2A
06/30 14:48, 2F

06/30 14:48, , 3F
超過很多才會有A3- 因為Ka非常小 要強鹼環境才解離
06/30 14:48, 3F

06/30 14:49, , 4F
沒Ka的話就拿磷酸試試看QQ 應該差不多像那樣
06/30 14:49, 4F
文章代碼(AID): #1FxUlP8d (TransBioChem)