Is KHC8H4O4 an acid?
Some primary standard acids are potassium hydrogen phthalate (KHP), oxalic acid dihydrate, sulfamic acid, and benzoic acid. The primary standard acid we will use in this experiment is KHP (1), the monoprotic potassium salt of a diprotic carboxylic acid (KHC8H4O4).
What is the Ka of potassium hydrogen phthalate?
3.91 x 10-6
Part 3: Project
| weak acid | dissociation constant, Ka |
|---|---|
| potassium hydrogen phthalate | 3.91 x 10-6 |
| acetic acid | 1.75 x 10-5 |
| formic acid | 1.77 x 10-4 |
| salicylic acid | 1.05 x 10-3 |
Is KHP a weak or strong acid?
Potassium hydrogen phthalate ( KHP ) has the molecular formula C8H5KO4 and is known to be a weak acid. Because the concentration of water is presumed constant and therefore not included in the expression, the equilibrium constant for this reaction is called acid dissociation constant, Ka .
What is the pKa of phenolphthalein?
9.3
Phenolphthalein has a pKa of 9.3. When conducting a titration of an acid analyte with a base titrant using phenolphthalein as the indicator, the pH will be low at the beginning, so the phenolphthalein will be mostly in the un-ionized or “protonated” “acid” form (we’ll refer to as HIn).
What is the molar mass of KHC8H4O4?
204.22 g/molPotassium hydrogen phthalate / Molar mass
Calculate the mass of KHC8H4O4 (molar mass = 204.23 g/mol) that reacts with 15 mL of 0.15 M NaOH….
Why must NaOH be standardized?
The reason we must standardize strong base solutions is because substances like NaOH will naturally absorb moisture from the air and react with gases in the air, such as CO2, to produce unwanted impurities in the stock sample of the base.
What is the pH of potassium hydrogen phthalate?
The pKa of KHP is 5.4, so it’s pH buffering range is 4.4 to 6.4….Potassium hydrogen phthalate.
| Names | |
|---|---|
| Density | 1.636 g/cm3 |
| Melting point | ~295 °C (decomposes) |
| Solubility in water | 80 g/L (20 °C) |
| Solubility | slightly soluble in alcohol |
How does KHP dissociate?
KHP dissociates completely in water, giving the potassium cation (K+) and hydrogen phthalate anion (HP− or Hphthalate−). And then as a weak acid hydrogen phthalate reacts reversibly with water to give hydronium (H3O+) and phthalate ions.
What is phenolphthalein class 7th?
(c) Phenolphthalein: Phenolphthalein is an indicator solution which turns colourless in the presence of acids. Therefore, in the presence of sulphuric acid, phenolphthalein turns colourless.
What is phenolphthalein alkalinity?
phenolphthalein alkalinity (FEE-nol-THAY-leen) The alkalinity in a water sample measured by the amount of standard acid required to lower the pH to a level of 8.3, as indicated by the change in color of phenolphthalein from pink to clear.
What are the values of PKA in organic chemistry?
pKa Data Compiled by R. Williams page-1 pKa Values INDEX Inorganic 2 Phenazine 24 Phosphates 3 Pyridine 25 Carboxylic acids 4, 8 Pyrazine 26 Aliphatic 4, 8 Aromatic 7, 8 Quinoline 27 Phenols 9 Quinazoline 27 Alcohols and oxygen acids 10, 11 Quinoxaline 27 Amino Acids 12 Special Nitrogen Compounds 28 Peptides 13 Hydroxylamines 28
What is the certified value for KHP crystalline material?
The certified value for KHP crystalline material is: 99.9934% ± 0.0076% for 95% confidence level, which is based on results from constant current coulometric titration of KHP solutions by OH-. Based on information above, answer questions 1-5. Natimtal of Certificate of Standard Reference Material* 84L Potassium Hydrogen Phthalate
What is the pKa of protonated alcohol?
1. Protonated carbonyl pKa = ‐7 Other important pKa’s 2. Protonated alcohol or ether pKa = ‐2 to ‐3 H2 = 35 3. Carboxylic acid pKa = 4‐5 4. Ammonium ion pKa = 9‐10 5. Phenol pKa = 10 6. Thiol pKa = 10 7. Alcohol pKa = 16‐18 8. Water pKa = 15.7 9. Amide pKa = 18 10.
What is KHP used for titration?
Cm B C) 90 Potassium hydrogen phthalate (KHP) is a widely used primary standard (functioning as a mono- protic acid) for acid/base titrations. The titration curve in Table 1 shows an example of using KHP to determine NaOH concentration (a process called standardization).