Effects of OH- Increase on Alkalinity, Acidity, and pH

In summary, adding OH- to a solution will increase its alkalinity and decrease its acidity. This is because OH- ions bond with H+ ions, which are responsible for acidity. The concept of pH is defined as the negative log of the concentration of H+ ions, while pOH is the negative log of the concentration of OH- ions. Increasing the concentration of OH- ions will result in a higher pH and therefore a decrease in acidity. It is important to note that pH and pOH are inversely related, with the sum of the two always equaling 14.
  • #1
n108
13
0
An increase in the OH- in a solution would result in

an increase in alkalinity (baseness).

an increase in acidity.

a pH of 7.

a decrease in pH.

i think it would be - an increase in alkalinity, but I am not sure
help!
 
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  • #2
When you add OH- to a solution, what does it bond with (i.e. remove some of from the solution)?

And what does that have to do with the definition of pH?

You're correct, but you should be able to be more confident in your guess
 
  • #3
Thanks for the help!
 
  • #4
pH is the negative of the log of the concentration of H3O+ ions (sometimes also called H+ ions) so the formula is:
pH = -log[H3O+]

The same is true for pOH except this time you are looking at the concentration of OH- ions:
pOH = -log[OH-]

And always remember pH + pOH = 14
so yes, if you increase the OH- ion concentration, you increase Alkalinity (and decrease acidity)
 

What is the definition of alkalinity?

Alkalinity refers to the ability of a solution to resist changes in pH when an acid or base is added. It is a measure of the concentration of basic ions, such as OH-, in a solution.

How does an increase in OH- affect alkalinity?

An increase in OH- ions leads to an increase in alkalinity. This is because OH- ions are basic and can neutralize acidic ions, thereby increasing the solution's ability to resist changes in pH.

What is the relationship between alkalinity and acidity?

Alkalinity and acidity are opposite properties. An increase in alkalinity leads to a decrease in acidity, and vice versa. This is because acidic and basic ions neutralize each other, resulting in a more balanced pH.

How does an increase in OH- affect acidity?

An increase in OH- ions leads to a decrease in acidity. This is because OH- ions react with H+ ions, the main contributor to acidity, to form water molecules. As a result, the concentration of H+ ions decreases and the solution becomes less acidic.

How does an increase in OH- affect pH?

An increase in OH- ions results in an increase in pH. This is because OH- ions are basic and can neutralize acidic H+ ions. As a result, the concentration of H+ ions decreases and the pH of the solution increases.

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