山 節 asked in 科學化學 · 1 decade ago

有ph值15和ph值-5

有ph值15和ph值-5 用廣用試紙是什麼顏色? 還有 PH 15 & PH -5 的化學物值有那些 .

5 Answers

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  • Tiger
    Lv 5
    1 decade ago
    Favorite Answer

    廣用試紙是藉著混合一些指示劑,來擴大偵測的pH範圍。一個常見的例子包括了甲基橙、甲基紅、溴瑞香草藍、phenolphthalein等,它的顏色變化從紅色(pH3)到紫色(pH10)。在實驗室裡,因為能夠快速偵測pH值,所以這樣的試紙幾乎都已取代舊型的石蕊試紙。 For pH > 10, the color is 紫色 while 紅色 for smaller than 3, so pH 15 --> 紫色 and pH (-5) --> 紅色In general, if you need to prepare pH 15, you can add a large amount of NaOH into water and adjust the final concentration of NaOH larger than 1mole/L (1M).In the case of pH(-5), you can add HCl into water to make a highly concentrated solution with the concentration of 10^5 mole/L (100000M).

    2006-04-29 23:30:19 補充:

    豆豆, that is great idea...

    Source(s): from Tiger
  • 1 decade ago

    Tiger解釋的很好!

    pH可以負也可超過14

    廣用試紙的來由謝謝Tiger的介紹

    還有要補充的一點是,

    要令pH小於0或是使之超過14

    除了改變濃度的方法

    也可以改變溫度→改變水的離子積

    使原本溶液的pH值改變

    因此,並沒有所謂PH 15 & PH -5 的化學物質

    一切都以這個化學物質的溶液濃度為準

  • 我想也是和原本一樣,ph值愈高,鹼性愈強;ph值愈低,酸性愈強。

    Source(s): 自己
  • 1 decade ago

    PH=-log[H+],是可以超過15或是負值的!

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  • 我只聽過 pH 是從 1 到 14......從來沒聽過 pH值 15和 pH值有負的..........

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