pH和POH之间的差异

Key Difference – pH vspOH

术语pH和pOH用于表达h的量⁺噢,^–离子存在于aqueoussolution. These expressions are given as minus log values of the concentration of solute. pH refers to the “potential of hydrogen”. It can be used to determine whether a solution is酸性,基本的或者neutral. In contrast, pOH is a measure ofhydroxideion (OH^–) concentration. Thekey differencebetween pH and pOH is thatphis a measure of hydrogen ions whereas pOH is a measure of hydroxide ions.

内容

1.Overview and Key Difference
2.什么是pH
3.什么是poh
4.Relationship Between pH and pOH
5.Side by Side Comparison – pH vs pOH in Tabular Form
6。概括

什么是PH？

phis a figure expressing the酸度或者alkalinityof a solution on a logarithmic scale on which 7 is neutral. The values lower than 7 are more acidic while higher values more alkaline. The pH is equal to −log₁₀c，其中c是每升摩尔的氢离子浓度。

The pH scale runs from 1 to 14. The pH values 1 to 6 is recognized as acidic pH values. The pH values from 8 to 14 are recognized as basic pH values. The pH 7 is considered as the neutral pH. For example, strong acids have a pH value near pH=1 whereas strong bases have pH values near pH=14. The “p” in the term pH refers to the negative logarithm. In general, the negative logarithm of the hydrogen ion concertation (or pH) is used instead of using the concentration of hydrogen ions. That is because, most of the times, the concentrations of hydrogen ions is very low or very large, thus, using pH makes it easier to work with such small or large values.

In aqueous solutions, the water molecules dissociate into hydrogen ions and hydroxide ions. Hence, all natural water bodies have a certain pH value. The pH of a system is given by the following equation.

ph= −log₁₀[H⁺]

有一些指标称为pH指标，用于指示酸碱反应的终点。这些指标能够随着pH的变化改变反应介质的颜色。例如，苯甲胺蛋白指示剂在基本pH值（大约pH = 10.0）中具有粉红色，但在pH = 8.3左右无色。

什么是poh？

POH是氢氧化离子的量度（哦^–) concentration. Hence, pOH is a measure of the alkalinity of a solution. The “p” in the term pOH refers to the negative logarithm. hence the pOH is the negative logarithm of hydroxide ion concentration in a solution.

ph= −log₁₀[OH^–]

由于该术语给出了水溶液中存在的氢氧化离子数量，因此它是碱性（碱度）的量度。例如，POH值小于POH = 7（在25^oC) are alkaline. Then, if a solution has a pOH value in between 1 to 6, the solution is more alkaline. pOH=7 is considered as neutral. But pOH values higher than 7 are recognized as acidic conditions.

What is the Relationship Between pH and pOH?

For the dissociation of water, the dissociation constant is given as below.

H₂o⇆h⁺+哦^–

K_w= [H⁺][哦^–]

Where kw is dissociation constant of water, [H⁺] is hydrogen ion concertation and[OH^–]是氢氧化离子浓度。但是对于纯水，[H⁺] = [OH^–] = 1×10^-7mol/L. then, when the negative logarithms are taken for each term in the above equation,

pKw = pH + pOH

pKw = 7 + 7

pKw = 14

then if only the pH is known, the pOH value can be obtained sing above relationship.

However, in both pH and pOH scales, 7 is neutral.

What is the Difference Between pH and pOH?

phvs pOH
phexpresses the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral.	POH是氢氧化离子的量度（哦–) concentration. pOH=7 is considered as neutral
Expression
phgives the negative logarithm of hydrogen ion concentration.	pOH gives the negative logarithm of hydroxide ion concentration.
Acidic Values
pH量表从1到6给出酸性值。	pOH scale gives acidic values from 8 to 14.
Alkaline Values
phscale gives basic values from 8 to 14.	pOH规模从1到6的基本价值观。

概括–phvspOH

phand pOH are two terms used to express the acidity or alkalinity of a solution. The main difference between pH and pOH is that pH is a measure of hydrogen ions whereas pOH is a measure of hydroxide ions.

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You can download the PDF version of this article and use it for offline purposes as per citation note. Please download the PDF version here:pH和POH之间的差异

Reference:

1.Helmenstine，Anne Marie，D。“ POH定义（化学）。”ThinkCo，2017年7月24日。Available here
2.Helmenstine, Anne Marie, D. “How to Find pOH in Chemistry.” ThoughtCo, Jan. 29, 2018.Available here

Image Courtesy:

1.汉斯·基尔肯多尔（Hans KirkendollCommons Wikimedia
2.’PHscalenolang’By PHscalenolang.png – Own work(CC BY-SA 2.5)viaCommons Wikimedia