pH vs. pOH — What's the Difference?
By Tayyaba Rehman — Published on October 2, 2023
pH measures the acidity of a solution, while pOH measures its basicity. Both values are related, and their sum is always 14 (at 25°C).
Difference Between pH and pOH
Table of Contents
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Key Differences
pH is a scale used to specify the acidity or basicity of an aqueous solution. On the other hand, pOH is utilized to denote the concentration of hydroxide ions, which tells us about the basicity of a solution.
When we discuss pH, we're referring to the concentration of hydrogen ions in a given solution. In contrast, pOH directly pertains to the concentration of hydroxide ions.
It's important to note that pH and pOH are inversely related. As the pH of a solution increases, indicating that it's becoming more basic, the pOH decreases, suggesting a decrease in its basicity.
In a neutral solution at 25°C, both pH and pOH have a value of 7. As the pH moves away from this value in either direction, the nature of the solution, acidic or basic, becomes more pronounced, and a similar but opposite movement is observed in pOH.
Comparison Chart
Represents
Acidity of a solution
Basicity of a solution
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Ion Concentration
Concentration of hydrogen ions (H+)
Concentration of hydroxide ions (OH-)
Relation
Decreases with increasing basicity
Decreases with increasing acidity
Neutral Value
7 at 25°C
7 at 25°C
Sum at 25°C
PH + pOH = 14
POH + pH = 14
Compare with Definitions
Ph
Negative logarithm of hydrogen ion concentration.
Pure water has a pH of 7, indicating neutrality.
Poh
Negative logarithm of hydroxide ion concentration.
The pOH of pure water is 7 at 25°C.
Ph
Measure of acidity.
Lemon juice has a low pH due to its acidic nature.
Poh
Scale complementary to pH.
Basic solutions have a pOH less than 7.
Ph
Indicator of hydrogen ion activity.
The pH of a solution changes with the addition of acid or base.
Poh
Measure of basicity.
Soap solutions have a high pOH due to their basic properties.
Ph
Reflects the acidic character of a solution.
The pH of soda is typically acidic.
Poh
Reflects the basic nature of a solution.
Cleaning solutions often have a high pOH.
Ph
Scale ranging from 0 to 14.
Acidic solutions have a pH less than 7.
Poh
Indicator of hydroxide ion activity.
The pOH decreases as a solution becomes more acidic.
Ph
A measure of the acidity or alkalinity of a solution, numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14.
Poh
Poh (Punjabi: ਪੋਹ, Punjabi pronunciation: [póː]) is the tenth month of the Nanakshahi calendar, which governs the activities within Sikhism. This month coincides with Pausha in the Hindu calendar and the Indian national calendar, and December and January in the Gregorian and Julian calendars and is 30 days long.
Ph
Abbr of phot
Poh
(dated) Indicating that something is trivial and not worth consideration.
Ph
Misspelling of pH
Poh
(dated) Expressing disagreement or irritation
Ph
Initialism of physical health
Poh
(dated) Expressing disgust or repulsion.
Ph
A notation used in transcripts to indicate that the transcriber does not know the spelling, usually of a name, and has spelled it as it was pronounced (phonetically)
Poh
(dated) Designating astonishment or that one is impressed.
Ph
(chemistry) p(otential of) H(ydrogen); the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and greater than 7 is acidic and less than 7 is basic)
Poh
An exclamation expressing contempt or disgust; bah !
Common Curiosities
What does pH measure?
pH measures the acidity of a solution.
What pH value indicates an acidic solution?
Any pH value less than 7 indicates an acidic solution.
What happens to the pOH of a solution if its pH increases?
If the pH increases, the pOH will decrease.
Can pH values be negative or exceed 14?
While the typical pH scale ranges from 0 to 14, under certain conditions, values can be negative or exceed 14.
How are pH and pOH related?
They are inversely related; their sum is always 14 (at 25°C).
What is the pH of a neutral solution?
The pH of a neutral solution is 7 at 25°C.
Can a solution have both high pH and high pOH?
No, as one increases, the other decreases.
Are pH and pOH absolute indicators of acid and base strength?
While they provide a measure, acid and base strength also depend on other factors like dissociation constants.
What is the significance of pOH?
pOH measures the basicity of a solution.
Why is pH important in daily life?
pH affects various processes, from digestion in our bodies to the health of plants and aquatic life.
How are pH and pOH values typically measured?
Using pH meters or indicators that change color based on the solution's acidity or basicity.
At what pOH value is a solution considered basic?
A solution is considered basic if its pOH is less than 7.
Which value, pH or pOH, would be used to measure the basicity of household cleaners?
pOH would be used to measure the basicity.
How can the pOH of a solution be determined if its pH is known?
By subtracting the pH value from 14 (at 25°C).
Does temperature affect pH and pOH values?
Yes, temperature can influence the pH and pOH of a solution.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
