What quantity (moles) of NaOH must be added to 1.0 L of 1.5 M HC2H3O2 to produce a solution buffered at pH = pKa? Ka = 1.8 x 10-5 Quantity = _______  mol What quantity (moles) of NaOH must be added to 1.0 L of 1.5 M HC2H3O2  to produce a solution buffered at pH = 4.00?                 Ka = 1.8 x 10-5 Quantity = _______  mol 3. What quantity (moles) of NaOH must be added to 1.0 L of 1.5 M HC2H3O2  to produce a solution buffered at pH = 5.00?   Ka = 1.8 x 10-5 Quantity = _______ mol

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  1. What quantity (moles) of NaOH must be added to 1.0 L of 1.5 M HC2H3Oto produce a solution buffered at pH = pKa?
    Ka = 1.8 x 10-5
    Quantity = _______  mol
  2. What quantity (moles) of NaOH must be added to 1.0 L of 1.5 M HC2H3O to produce a solution buffered at pH = 4.00?                 Ka = 1.8 x 10-5

Quantity = _______  mol

3. What quantity (moles) of NaOH must be added to 1.0 L of 1.5 M HC2H3O to produce a solution buffered at pH = 5.00? 

 Ka = 1.8 x 10-5

Quantity = _______ mol

 

(A similar solution is attached for reference) 

 

Added OH converts HC2 H3 02 into C2H3 02:
HC,H3O2 + OH C,H3O2 + H20
From this reaction, the moles of C2H3O2 produced equal the moles of OH added. Also, the total concentration of acetic acid plus acetate ion must equal 1.7 M (assuming no volume change on addition of NaOH).
[C,H3O2 ]+ [HC, H3 O2] = 1.7 M and
[C,HO2 ] produced = [OH ] added
[CH3 O2 ]
[HC,H3O]
Гон ] added
[C2H3 O2 ]
[HC,H,O]
pH = pK, + log
; for pH = pK,, log
a.
Therefore,
[CH,O2]
[HC,HO]
= 1.0 and [C,H3 O2 ] = [HC;H3O2]-
Because [C2 H3 02 ]+ [HC,H3 O2] = 1.7 M :
[C,H3O2] = [HC,H;O2] = 0.85 M = [OH ] added
To produce a 1.0 M C2H3O2 solution, we need to add 0.85 mol of NaOH to 1.0 L of the 1.7 M HC2H3O2 solution. The resulting solution will have pH = pK = 4.74.
[C,H3O2-] [CH3O2]
[HC, H3O]
HC,H3O]
b.
4.00 = 4.74 + log
10-0.74 = 0.18
%3D
[C,HO2 ] = 0.18[HC,H;O2] or
%3D
[HC,H,O2] = 5.5(C,H;O2]
Because (C2H3 O2 ]+ [HC,H3O2] = 1.7 M :
[CH3O2¯]+ 5.5(C,H,O2¯] = 1.7 M
1.7
[C,H3O2 ] =
0.26 M [OH] added
6.5
We need to add 0.26 mol of NaOH to 1.0 L of 1.7 M HC2H3O2 solution to produce 0.26 M C2H3O2.
The resulting solution will have pH = 4.00.
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Transcribed Image Text:Added OH converts HC2 H3 02 into C2H3 02: HC,H3O2 + OH C,H3O2 + H20 From this reaction, the moles of C2H3O2 produced equal the moles of OH added. Also, the total concentration of acetic acid plus acetate ion must equal 1.7 M (assuming no volume change on addition of NaOH). [C,H3O2 ]+ [HC, H3 O2] = 1.7 M and [C,HO2 ] produced = [OH ] added [CH3 O2 ] [HC,H3O] Гон ] added [C2H3 O2 ] [HC,H,O] pH = pK, + log ; for pH = pK,, log a. Therefore, [CH,O2] [HC,HO] = 1.0 and [C,H3 O2 ] = [HC;H3O2]- Because [C2 H3 02 ]+ [HC,H3 O2] = 1.7 M : [C,H3O2] = [HC,H;O2] = 0.85 M = [OH ] added To produce a 1.0 M C2H3O2 solution, we need to add 0.85 mol of NaOH to 1.0 L of the 1.7 M HC2H3O2 solution. The resulting solution will have pH = pK = 4.74. [C,H3O2-] [CH3O2] [HC, H3O] HC,H3O] b. 4.00 = 4.74 + log 10-0.74 = 0.18 %3D [C,HO2 ] = 0.18[HC,H;O2] or %3D [HC,H,O2] = 5.5(C,H;O2] Because (C2H3 O2 ]+ [HC,H3O2] = 1.7 M : [CH3O2¯]+ 5.5(C,H,O2¯] = 1.7 M 1.7 [C,H3O2 ] = 0.26 M [OH] added 6.5 We need to add 0.26 mol of NaOH to 1.0 L of 1.7 M HC2H3O2 solution to produce 0.26 M C2H3O2. The resulting solution will have pH = 4.00. Email
[C,H3 O2 ] [C,H3O2¯]
10 0.74 0.18
b.
4.00 = 4.74 + log
[HC, H3 O]
HC, H; O]
[C,H3O2 ] = 0.18(HC,H;O2] or
(HC,H3 O2] = 5.5[C,H3 O2]
Весause [C> Hз02] + (НС, Нз О2] 3 1.7 М:
[C,H; O2 ]+ 5.5[C,H3O2 ] = 1.7 M
1.7
[C,H3O2 ] =
= 0.26 M = [OH ] added
6.5
We need to add 0.26 mol of NaOH to 1.0 L of 1.7 M HC,H3 O2 solution to produce 0.26 M C2H3 O2.
The resulting solution will have pH = 4.00.
[C,H3 O2]
HC, H3 O]
[C,H3O2]
[HC,H3O]
5.00 = 4.74 + log
100.26 = 1.8
C.
1.8 HC, H;O2] =[C2H3O2 ] or
[HC,H3O2] = 0.56[C,H3O2 ]
1.56[C2H3O2 ] = 1.7 M
[C,H3O2-1 = 1.1 M = [OH ] added
We need to add 1.1 mol of NaOH to 1.0L of 1.7 M HC2H3O2 solution to produce a solution with pH = 5.00.
Transcribed Image Text:[C,H3 O2 ] [C,H3O2¯] 10 0.74 0.18 b. 4.00 = 4.74 + log [HC, H3 O] HC, H; O] [C,H3O2 ] = 0.18(HC,H;O2] or (HC,H3 O2] = 5.5[C,H3 O2] Весause [C> Hз02] + (НС, Нз О2] 3 1.7 М: [C,H; O2 ]+ 5.5[C,H3O2 ] = 1.7 M 1.7 [C,H3O2 ] = = 0.26 M = [OH ] added 6.5 We need to add 0.26 mol of NaOH to 1.0 L of 1.7 M HC,H3 O2 solution to produce 0.26 M C2H3 O2. The resulting solution will have pH = 4.00. [C,H3 O2] HC, H3 O] [C,H3O2] [HC,H3O] 5.00 = 4.74 + log 100.26 = 1.8 C. 1.8 HC, H;O2] =[C2H3O2 ] or [HC,H3O2] = 0.56[C,H3O2 ] 1.56[C2H3O2 ] = 1.7 M [C,H3O2-1 = 1.1 M = [OH ] added We need to add 1.1 mol of NaOH to 1.0L of 1.7 M HC2H3O2 solution to produce a solution with pH = 5.00.
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