(a)
Interpretation: The value of
Concept Introduction: The pH of buffer solutions can be calculated with the help of Henderson-Hasselbalch equation. The Henderson-Hasselbalch equation can be used that gives the relation between pH and
(b)
Interpretation: The reason of sodium bicarbonate to be a suitable base for separating phenol from a neutral organic compound needs to be explained.
Concept Introduction: The pH of buffer solutions can be calculated with the help of Henderson-Hasselbalch equation. The Henderson-Hasselbalch equation can be used that gives the relation between pH and
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EBK EXPERIMENTAL ORGANIC CHEMISTRY: A M
- Ethyne (HC‚CH) has a pKa value of 25, water has a pKa value of 15.7, and ammonia (NH3) has a pKa value of 36. Draw the equation, showing equilibrium arrows that indicate whether reactants or products are favored, for the acid–base reaction of ethyne with a. HO- . b. -NH2. c. Which would be a better base to use if you wanted to remove a proton from ethyne, HO- or -NH2?arrow_forward3. What is observed when the H2O concentration in the acetic acid equilibrium becomes relatively low? Relatively high? 4. Humidity indicator cards (HIC) are commonly added to semiconductor shipments to document that the parts were not exposed to humidity. These cards are impregnated with cobalt(II) chloride, or an alternative, and change color to indicate the presence of water. Predict the color you would see if a cobalt(II) chloride HIC were exposed to moist, humid air?arrow_forwardIf you have an unknown phenol, what pH you need to achieve upon re-acidification with HCl to ensure that your phenol is 99.9% back in its neutral form?Assume a pKa of 10 for your phenol, and remember that the pH needs to be 3 units different from the pKa for 99.9% ionization or neutralization. pH 5 or lower pH 7 or lower pH 13 or lower pH 2 or lowerarrow_forward
- Acid-Base Equilibria Many factors contribute to the acidity of organic compounds. Electronegativity, resonance, induction, hybridization, aromaticity, and atomic size, all play a role. In the following comparisons, you are asked to identify the factor(s) that would be most important to analyze when predicting relative acidity, and then to predict the trend in acidity and pKa values. For each of the following pairs of compounds answer the following two multiple-choice questions. 1. What factor(s) are the most important to consider when predicting the relative acidity of the two compounds? a. Electronegativity of the atom possessing the hydrogen. b. Resonance stabilization of the anionic conjugate base. c. Inductive stabilization of the anionic conjugate base. d. Hybridization of the atom possessing the hydrogen. e. The atomic size of the atom possessing the hydrogen.arrow_forwardWrite an equation for the acid-base reaction between 2,4-pentanedione and sodium ethoxide and calculate its equilibrium constant, Keq. The pKa of 2,4-pentanedione is 9; that of ethanol is 15.9.arrow_forwardLow-molecular-weight dicarboxylic acids normally exhibit two different pKa values. Ionization of the first carboxyl group is easier than the second. This effect diminishes with molecular size, and for adipic acid and longer chain dicarboxylic acids, the two acid ionization constants differ by about one pK unit. Why do the two pKa values differ more for the shorter chain dicarboxylic acids than for the longer chain dicarboxylic acids?arrow_forward
- Equilibrium of methyl orangea) Give a balanced reaction equation for the reaction of methyl orange with 6M HCl b) Give a balanced reaction equation for the reaction of methyl orange with 6M NaOHc) Use Le Chatelier’s Principle to explain the color change when acid or base is added to methyl Orange. Reaction: HMO = H^+ +MO^-arrow_forwardhydrogens on a carbon adjacent to a carbonyl group are far more acidic than those not adjacent to a carbonyl group. The anion derived from acetone, for example, is more stable than is the anion derived from ethane. Account for the greater stability of the anion from acetone. CH,ČCH, H CH,CH, H Acetone Ethane pK, 20.2 pK, 51arrow_forward2,4,6-Trinitrophenol is also called picric acid. Why is this substance called an acid? How is the acid strength affected by the substituting groups in this case? H NO₂ O₂N. NO₂arrow_forward
- Which of the following two acids has the stronger conjugate base? Nitrous acid, Ka = 7.1 x 10–4 Phenol, Ka = 1.0 x 10–10 The strength of the conjugate base cannot be obtained from the information given. Nitrous acid, because it has a larger Ka value. Nitrous acid, because it has a smaller Ka value. Phenol, because it has a larger Ka value. Phenol, because it has a smaller Ka value.arrow_forwardH3C—N̈H2 reacts with BF3 in a combination reaction, forming H3C—NH2—BF3 with a covalent bond between N and B. What is the role of H3C—N̈H2 in this reaction? a.Brønsted-Lowry acid b.Lewis base c.Brønsted-Lowry base d.Lewis acidarrow_forward
- Chemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage LearningOrganic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning