I want to thank your team (Jeff) for finding a new writer when you were unable to reach my existing writer to revise my paper. I appreciate your professionalism and efforts. Thanks
Report (any type)/Brief report
22/09/2021
##”pH” = 3.57##
Your buffer contains hydrofluoric acid, ##”HF”##, weak acid, and sodium fluoride, ##”NaF”##, the salt of its conjugate base, the fluoride anion, ##”F”^(-)##.
When the sodium hydroxide solution is added, assuming with no change in the total volume of the buffer, you can expect the weak acid and the strong base to each other.
Moreover, this reaction will result in the production of more conjugate base.
So, the balanced chemical equation for the reaction between hydrofluoric acid and sodium hydroxide looks like this
##”HF”_text((aq]) + “NaOH”_text((aq]) -> “NaF”_text((aq]) + “H”_2″O”_text((l])##
Notice that ##1## mole of hydrofluoric acid will react with ##1## mole of sodium hydroxide and produce ##1## mole of sodium fluoride.
Use the of the hydrofluoric acid and the volume of the buffer to determine how many moles you have in solution
##color(blue)(c = n/V implies n = c * V)##
##n_(HF) = “0.250 M” * “1.5 L” = “0.375 moles HF”##
Do the same for the conjugate base
##n_(F^(-)) = “0.250 M” * “1.5 L” = “0.375 moles F”^(-)##
Now, you’re adding ##0.0500## moles of sodium hydroxide to the buffer. Since you have fewer moles of strong base than on weak acid, it follows that the sodium hydroxide will be completely consumed.
The number of moles of hydrofluoric acid will be changed to
##n_(HF) = “0.375 moles” = “0.0500 moles” = “0.325 moles”##
The number of moles of fluoride anions will increase by the same amount
##n_(F^(-)) = “0.375 moles” + “0.0500 moles” = “0.425 moles F”^(-)##
Use the volume of the buffer to calculate the new molarities of the weak acid and its conjugate base
##[“HF”] = “0.325 moles”https://studydaddy.com/”1.5 L” = “0.21667 M”##
##[“F”^(-)] = “0.425 moles”https://studydaddy.com/”1.5 L” = “0.28333 M”##
Finally, use the Henderson – Hasselbalch equation to find the of the buffer
##color(blue)(“pH” = pK_a + log( ([“conjugate base”])/([“weak acid”]))##
Use the acid dissociation constant, ##K_a##, to get the value of ##pK_a##
##pK_a = – log(K_a)##
The pH of the solution will thus be
##”pH” = -log(K_a) + log( ([“F”^(-)])/([“HF”]))##
##”pH” = -log(3.5 * 10^(-4)) + log( (0.28333color(red)(cancel(color(black)(“M”))))/(0.21667color(red)(cancel(color(black)(“M”)))))##
##”pH” = color(green)(3.57)##
Finally, does this result make sense?
Notice that your starting buffer had equal concentrations of weak acid and conjugate base. This means that the H-H equation can be reduced to
##”pH” = pK_a + log(1) = pK_a##
Initially, the pH of the solution was equal to ##3.46##.
The buffer then converts the strong base to weak base, and so the concentration of conjugate base is bigger than that of the weak acid. This is why the pH of the buffer increases after the addition of the strong base.
I want to thank your team (Jeff) for finding a new writer when you were unable to reach my existing writer to revise my paper. I appreciate your professionalism and efforts. Thanks
Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.
You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.
Read moreEach paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.
Read moreThanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.
Read moreYour email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.
Read moreBy sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.
Read more