Tell whether the pH at equivalence point is less than 7, greater than 7 or equal
ID: 522310 • Letter: T
Question
Tell whether the pH at equivalence point is less than 7, greater than 7 or equal to 7 for each of the following solutions. PLEASE SHOW WORK IF POSSIBLE OR EXPLAINATION; Thank you so much!
12. 0.1M acetic acid with 90.10M NaOH
a). Greater than 7
b.) Equal to 7
c.) Less than 7
d.) Equal to 14
e.) Don't Know
13. 0.050M formic acid (HCOOH) with 0.0930M NaOH
a.) Greater than 7
b.) Less than 7
c.) Equal to 7
d.) Equal to 1.0
e.) Equal to 9
14. 0.050M NaOH with 0.50M HCl
a). Equal to 7
b.) Greater than 7
c.) Less than 7
d.) Equal to 14
e.) Equal to 1.0
15. 0.2M HCl with 0.2M NH3
a.) Less than 7
b.) Equal to 7
c.) Greater than 7
d.) Equal to 7
e.) Equal to 0.0
Explanation / Answer
12. CH3COOH + NaOH ----------> CH3COONa + H2O
I 0.1 90.1 0
C -0.1 -0.1 0.1
E 0 90
[OH-] = 90M
POH = -log[OH-]
= -log90 = -1.9542
PH = 14-POH
= 14-(-1.9542) = 15.9542>>>>equalt ot 14
d.) Equal to 14
13. HCOOH + NaOH -------------> HCOONa + H2O
I 0.05 0.093 0
C -0.05 -0.05 0.05
E 0 0.043 0.05
[OH-] = 0.043M
POH = -log[OH-]
= -log0.043 = 1.3665
PH = 14-POH
= 14-1.3665 = 12.6335
a.) Greater than 7
14 acid conc is more
c.) Less than 7
15. NH4+ +H2O ---------> NH4OH + H+
I 0.2 0 0
C -x +x +x
E 0.2-x +x +x
Ka = {NH4OH][H+]/[NH4+]
5.6*10^-10 = x*x/0.2-x
5.6*10^-10*(0.2-x) = x^2
x = 1.06*10^-5
[H+] = x= 1.06*10^-5
PH = -log[H+]
= -log1.06*10^-5 = 4.9746
a.) Less than 7
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