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The Kpw of NaOH

Posted: Thu Mar 30, 2023 8:21 pm
by A1高闪
there is a question about the Kpw of NaoH is what.How to calculate the ph?

Re: The Kpw of NaOH

Posted: Fri Mar 31, 2023 1:03 am
by ChenBeier
Kpw = 14 = pH + pOH-
pH = 14 - pOH
pOH = - log(cOH-)
pH = 14 + log(cOH-)

Re: The Kpw of NaOH

Posted: Thu May 11, 2023 12:44 am
by hodkiewicz
Concentration of NaOH=Concentration of OH- ions (NaOH is a strong base)

Kw=1x10^-14 (at room temperature/25 degrees)

using Kw=[H+][OH-]

Re: The Kpw of NaOH

Posted: Thu May 11, 2023 2:26 am
by ChenBeier
Not necessary to repeat, its already written above.

Re: The Kpw of NaOH

Posted: Tue Dec 26, 2023 11:56 pm
by Kestrel
I have a detailed explanation for those who need it:

To calculate the pH of a solution of NaOH, you need to consider the concentration of the NaOH solution. The pH is a measure of the acidity or alkalinity of a solution and is determined by the concentration of hydrogen ions (H+) present.

Here's the general procedure to calculate the pH after determining the concentration of NaOH:

Determine the concentration of NaOH solution: This can be given in different units, such as molarity (M) or percent (%). Let's assume you have the concentration in molarity (M).

Write the balanced chemical equation for the dissociation of NaOH in water: NaOH dissociates completely in water to produce Na+ ions and OH- ions. The equation is NaOH -> Na+ + OH-.

Determine the concentration of OH- ions: Since NaOH is a strong base, the concentration of OH- ions will be equal to the concentration of NaOH.

Calculate the pOH: pOH is the negative logarithm (base 10) of the concentration of OH- ions. It is calculated using the formula: pOH = -log[OH-].

Calculate the pH: The pH is related to the pOH by the equation: pH + pOH = 14. Rearrange the equation to solve for pH: pH = 14 - pOH.

Calculate the final pH: Substitute the value of pOH from step 4 into the equation in step 5 to calculate the pH.

Remember to be consistent with units throughout the calculations. If you have the concentration of NaOH in percent (%), you will need to convert it to molarity (M) before proceeding with the calculations.

Note that the value of pKw (the ionization constant of water) is approximately 14 at room temperature, which is used in the pH calculation.

It's important to note that NaOH is a strong base, and if added to water in sufficient quantity, it will fully dissociate, resulting in a highly alkaline solution with a pH greater than 7.

Re: The Kpw of NaOH

Posted: Wed Dec 27, 2023 4:23 am
by ChenBeier
The thread is from march. Dont answer old threads and the answers where already given.