Formic acid,HCHO2 , is used to make methyl formate (a fumigant
for dried fruit) and ethyl formate (an artificial rum flavor). What
is the pH of a 0.26 M solution of formic
acid? What is the degree of ionization of HCHO2 in this
solution
The formate ion, HCO2-, is formed when formic acid dissolves in water. A number of possible resonance structures for this ion are shown.
Which of these structures are valid and which are invalid?
Drag each item to the appropriate bin.
(a) What is the pH of 0.89 M potassium formate, HCOOK?
(The Ka of formic acid is
1.8 ✕ 10−4.)
(b) What is the pH of 0.65 M NH4Br? (The
Kb of ammonia is
1.76 ✕ 10−5.)
An aqueous solution of formic
acid, that is 1.00 percent by weight
formic acid, has a density of
1.0006 g/mL. A student determines that the
freezing point of this solution is -0.421 °C.
Based on the observed freezing point,
what is the percent ionization of the acid and the value of
Ka?
Kf for H2O is 1.86 °C/m.
The pKa of formic acid was measured by titrating a 1.00 mM
solution of formic acid with NaOH in the presence of varied
concentrations of NaCl. The results are as listed:
NaCl (mM)
10
25
50
100
200
pKa
4.65
4.58
4.53
4.45
4.40
utilize a graphical method to determine the true pKa of formic
acid (debye-huckle is valid)
Provide step by step instructions if excel is utilized.
1. Use the Henderson-Hasselbalch equation to determine the ratio
of base/acid in a formic acid-formate buffer with a pH of 3.00
2. Assume that the human blood buffer includes, at any one
point, 0.00080 M carbonic acid and 0.0080 M hydrogen carbonate.
What is the pH of 7.00 liter of blood under these conditions?
3. Metabolic acidosis results in the addition of excess acid to
blood. How many moles of strong acid must be added to the blood in
question...
12. Calculate the pH of a 0.10 M solution of potassium formate,
KHCOO. Ka of formic acid (HCOOH) = 1.8 x 10^-4. Write the
dissociation equation and label each ion as acidic, basic, or
neutral. Also write the hydrolysis equation.
Dissociation equation: _____________________________________
cation: __________ anion: __________
Hydrolysis equation:
_________________________________________________________________________
A.You have 1 M solutions of formic acid and
sodium formate. Calculate the volume of sodium formate required to
make 1 liter of a solution with a pH of 4.1 in which the
concentration of formic acid is 0.15 M. The pKa of formic acid is
3.75.
B. Using the Henderson-Hasselbalch equation,
explain why the pH of a solution of a weak acid and its conjugate
base does not change upon dilution.
2.0 mL of 0.5M HCl was added to 50 mL of 0.5M Formate-formic
acid buffer at pH 3.6. (pKa= 3.75) What is the resulting pH after
the addition of HCl?
2.0 mL of 0.5M HCl was added to 50 mL of 0.0625M Formate-formic
acid buffer at pH 3.6. (pKa= 3.75) What is the resulting pH after
the addition of HCl?
1.0 mL of 0.6M NaOH was added to 10 mL of 0.5M Acetate-acetic
acid buffer at pH 4.2. What is...