Business
Engineering
Math
Science
Social ScienceA buffer solution contains 0.462 M CH3NH3Br and 0.381 M CH3NH2 (methylamine). Determine the pH change when 0.082 mol KOH is added to 1.00 L of the buffer.pH after addition − pH before addition = pH change = ______
A buffer solution contains 0.462 M CH3NH3Br and 0.381 M CH3NH2 (methylamine). Determine the pH change when 0.082 mol KOH is added to 1.00 L of the buffer.
pH after addition − pH before addition = pH change = ______
Expert Answer
pKb of CH3NH2 is 3.36.
pOH of the solution can be determined using Henderson-Hasselbalch equation. pH can be determined from the pOH value as follows,
![Henderson Hasselbalch expression:
[Conjugate acid]
Base
РОН 3 рК, +1оg
[CH,NH,Br
[CH,NH2
(0.462 M)
' (0.381 M
=3.36 log
= 3.36+log
= 3.44
PH + pОН %3D 14
pH 3 14-рОН
14-3.44
10.56
Hence, pH of the solution before adding KOH is 10.56](https://prod-qna-question-images.s3.amazonaws.com/qna-images/answer/dc9b1e19-3178-4109-8565-e06c678af57f/4e4e1b4f-4294-4689-8ddf-2e2229814906/sv0gz3.png)
Image Transcriptionclose
Henderson Hasselbalch expression: [Conjugate acid] Base РОН 3 рК, +1оg [CH,NH,Br [CH,NH2 (0.462 M) ' (0.381 M =3.36 log = 3.36+log = 3.44 PH + pОН %3D 14 pH 3 14-рОН 14-3.44 10.56 Hence, pH of the solution before adding KOH is 10.56
On addition of KOH, it reacts with CH3NH3Br forming CH3NH2. Hence, concentration of CH3NH3Br decreases whereas concentration of CH3NH2 increases after the addition of KOH. Hence, the concentration of CH3NH3Br and CH3NH2 is calculated.
Image Transcriptionclose
CH,NH OH - > CH,NH2H0 Concentration of KOH No. of moles x Volume(in L) (0.082 mol)(1.00 L) = 0.082 M = [CH,NH,Br after adding KOH= (0.462 M)-(0.082 M) 0.380 M CHNH after adding KOH = (0.381 M) +(0.082 M) = 0.463 M
pH of the solution after adding KOH ...
![[Conjugate acid]
Base
РОН - рК, +1оg
CH,NH,Br]
[CH,NH2
(0.380 M)
=3.36+log
= 3.36 +log
= 3.27
'(0.463 M)
PH + pОН 3 14
рH — 14- рОН
= 14-3.27 = 10.73
Hence, pH of the solution after adding KOH is 10.73](https://prod-qna-question-images.s3.amazonaws.com/qna-images/answer/dc9b1e19-3178-4109-8565-e06c678af57f/4e4e1b4f-4294-4689-8ddf-2e2229814906/k534xso.png)
Image Transcriptionclose
[Conjugate acid] Base РОН - рК, +1оg CH,NH,Br] [CH,NH2 (0.380 M) =3.36+log = 3.36 +log = 3.27 '(0.463 M) PH + pОН 3 14 рH — 14- рОН = 14-3.27 = 10.73 Hence, pH of the solution after adding KOH is 10.73
Science
Chemistry
Equilibrium Concepts
Related Chemistry Q&A
Find answers to questions asked by student like you
Show more Q&A addQ: Which of these chemical equations does NOT describe a redox reaction? Group of answer choices 2K...
A: The Oxidation number is predicted for the element in the given reactions as shown,
Q: #5
A: 1,3-diaxial steric strain for a single (-OH---H) = 2.1 kJ/mol1,3-diaxial steric strain for a single ...
Q: The following reaction forms 14.0 g of Ag(s): 2Ag2O(s)→4Ag(s)+O2(g) Part A What to...
A: The values are given as follows:
Q: Use the equation to answer the question. Cl2+F2--> ClF3 How many grams of ClF3 form when 0.204 mo...
A: The balanced chemical reaction is given below.
Q: What is the molar mass of anhydrous KAl(SO4)2? (step by step equation)
A: The given compound KAl(SO4)2 is potassium aluminium sulfate. It consists of one potassium atom, one ...
Q: In the balanced oxidation-reduction reaction (occurring in acidic condition) the coefficients before...
A: The oxidation number of the sulfur atom in sulfite ion and nitrogen atom in nitrate ion is +4 and +5...
Q: 8.83 Construct a Born-Haber cycle for the formation of the hy- pothetical compound NaCl2, where the ...
A: Born-Haber cycle for the formation of hypothetical compound NaCl2 is constructed as follows,
Q: Ascorbic acid (vitamin C) is a weak diprotic acid. What isthe pH of 0.250 M ascorbic acid?
A: Let H2A represent ascorbic acid.As Ka1>>> Ka2=> only need to consider first dissociation...
Q: Match the name of the ionic solid with the number of ions which would be formed when the solid is di...
A: All the given three ionic compounds are completely dissolves in water.
