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What volumes of 0.200 m hcooh and 2.00 m naoh would make 500 ml of a buffer with the same pH as of one made from 475 ml of 0.200 m benzoic acid and 25 ml of 2.00 m naoh?
Wiki User
∙ 13y ago
In general buffer the Henderson/Hasselbach equation is valid to use:
pH = pKa -log [(Ca)/(Cb)]
In which:
* Ca = concentration of weak acid (benz. or formic.acid) and
* Cb = conc'n of their respective conjugated bases (benzoate and formiate)
From tables it is found: pKbenz.acid = 4.20 and pKformic.acid = 3.80
pHbenz.acid,sol'n = 4.20 - log[(475*0.200-25*2.00)/(25*2.00)] =
= equal pH values =
= pHformic.acid sol'n = 3.80 - log[(Va*0.200-Vb*2.00)]/(Vb*2.00)]
in which Va + Vb = 500 mL of the (new) HCOOH/HCOO- buffer
* Va = volume of the formic acid sol'n (HCOOH, in mL) and
* Vb = volume of the (2.00M) NaOH sol'n.
The rest is calculation. Outcome:
equal pH values: pH = 4.246
- log [(Va*0.200-Vb*2.00)]/(Vb*2.00)] = 4.246 - 3.80 = 0.446
[(Va*0.200-Vb*2.00)]/(Vb*2.00)] = 0.358
Va*0.200/Vb*2.00 - 1 = 0.358
0.100*Va/Vb = 1.358
Va = 13.58*Vb and with Va + Vb = 500 it comes to:
Va= 465.5 mL and Vb = 34.5 mL
Wiki User
∙ 13y ago
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Why is methanoic acid more acidic than benzoic acid?
We would certainly expect benzoic acid to be more acidic than methanoic acid, due to stabilisation of the benzoate anion caused by the delocalisation of the electrons on the oxygen atom over the benzene ring. However, in practice, it is found that methanoic acid is actually more acidic than benzoic acid(has a greater Ka value). This is because methanoic acid is more soluble in water than benzoic acid, so there is greater ionisation of methanoic acid in water than benzoic acid.
What results from a mixture of benzoic acid to and HCL?
You will get benzoic acid as a result. The benzoic salt will gain a Hydrogen from the HCl; thus, becoming benzoic acid, and the Cl shall remain by itself in suspension if you're mixing the two together in an aqueous solution.
What would the effect of reagent such as control buffer substrate buffer and ascorbic acid be on the browning process?
prevents food from browning
Does Benzoic Acid react with Hypochlorous Acid in water and room temperature?
I assume that it will not react because benzoic acid cannot be oxidized easily by the hypochlorous acid. I would not try this at a large scale without appropriate safety measures though!
What substance would you add to NaHCO3 to form a buffer solution?
The mixture Na2CO3 + NaHCO3 is a buffer in the range 9,2-10,8 pH.
Would benzoic acid particles adhere to a magnet?
Yes
If benzoic acid were heated at 140 degrees Celsius what would happen?
When Benzoic acid is heated beyond its boiling point, it starts precipitating snow like solids.
How many tokens a buffer can hold?
That would depend on the size of the buffer.
What would a graph about masses and volumes represent?
A graph about masses and volumes would represent density.
What is the plural for buffer?
"Buffers" would be the plural.
Why is methanoic acid more acidic than benzoic acid?
We would certainly expect benzoic acid to be more acidic than methanoic acid, due to stabilisation of the benzoate anion caused by the delocalisation of the electrons on the oxygen atom over the benzene ring. However, in practice, it is found that methanoic acid is actually more acidic than benzoic acid(has a greater Ka value). This is because methanoic acid is more soluble in water than benzoic acid, so there is greater ionisation of methanoic acid in water than benzoic acid.
When would you use milliliters?
When you want to measure small volumes or larger volumes to a high degree of accuracy.
What results from a mixture of benzoic acid to and HCL?
You will get benzoic acid as a result. The benzoic salt will gain a Hydrogen from the HCl; thus, becoming benzoic acid, and the Cl shall remain by itself in suspension if you're mixing the two together in an aqueous solution.
What would the effect of reagent such as control buffer substrate buffer and ascorbic acid be on the browning process?
prevents food from browning
Does Benzoic Acid react with Hypochlorous Acid in water and room temperature?
I assume that it will not react because benzoic acid cannot be oxidized easily by the hypochlorous acid. I would not try this at a large scale without appropriate safety measures though!
Why is it necessary to filter the benzoic acid solution while hot?
At low temperature it has poor solubility and would crystallize out
What substance would you add to NaHCO3 to form a buffer solution?
The mixture Na2CO3 + NaHCO3 is a buffer in the range 9,2-10,8 pH.
