Label the acid and base, and the conjugate acid and base in the following reactions. Use

a. Which compounds are BrnstedLowry acids: HBr, NH3, CCl4? b. Which compounds are BrnstedLowry bases: CH3CH3, (CH3)3CO , HC CH? c. Classify each compound as an acid, a base, or both: CH3CH2OH, CH3CH2CH2CH3, CH3CO2CH3.

a. Draw the conjugate acid of each base: NH3, Cl , (CH3)2C O. b. Draw the conjugate base of each acid: HBr, HSO4 , CH3OH

The presence of a bond also makes a compound a base. With this in mind, draw the conjugate acid of ethylene, CH2 CH2. What is ethylenes conjugate base?

Label the acid and base, and the conjugate acid and base in the following reactions. Use curved arrows to show the movement of electron pairs. a. HCl + + H2O Cl H3O+ b. + + CH3 C CH3 O OCH3 CH3OH CH3 C CH2 O

Draw the products of each proton transfer reaction. a. CCl3CO2H + OCH3 c. CH3NH2 + HCl b. H CH C + H d. CH3CH2OH + H2SO4

Draw the products formed from the acidbase reaction of HCl with each compound. a. CH3OH b. (CH3CH2)2O c. (CH3)3N d. NH

Which compound in each pair is the stronger acid? a. CH3CH2CH3 or CH3CH2OH b. OH = = CH3 Ka 1010 Ka 1041 or pKa = 50 pKa = 16

Use a calculator when necessary to answer the following questions. a. What is the pKa for each Ka: 1010, 1021, and 5.2 105? b. What is the Ka for each pKa: 7, 11, and 3.2?

Rank the conjugate bases of each group of acids in order of increasing basicity. a. NH3, H2O, CH4 b. CH2 CH2, HC CH, CH4

Estimate the pKa of each of the indicated bonds. a. H N H b. O H c. BrCH2COO H

Draw the products of each reaction and determine the direction of equilibrium. a. CH2 CH2 H + c. CH3COOH + CH3CH2O b. CH4 + OH d. Cl + CH3CH2OH

Answer the following questions by referring to Table 2.1: a. Which of the following bases is strong enough to deprotonate CH3COOH: H , HC C , and Cl ? b. List four bases that are strong enough to deprotonate HC CH.

Using the data in Appendix A, determine which of the following bases is strong enough to deprotonate acetonitrile (CH3CN) so that equilibrium favors the products: (a) NaH; (b) Na2CO3; (c) NaOH; (d) NaNH2; (e) NaHCO3.

Without reference to a pKa table, decide which compound in each pair is the stronger acid. a. NH3 or H2O b. HBr or HCl c. H2S or HBr

Which compound in each pair of isomers is the stronger acid? a. CH3CH2CH2NH2 or (CH3)3N b. CH3CH2OCH3 or CH3CH2CH2OH

Which hydrogen in each molecule is most acidic? a. CH3CH2CH2CH2OH b. HOCH2CH2CH2NH2 c. (CH3)2NCH2CH2CH2NH2

Which hydrogen in pseudoephedrine, the nasal decongestant in the commercial medication Sudafed, is most acidic? OH N H pseudoephedrine

Which compound in each pair is the stronger acid? a. ClCH2COOH or FCH2COOH c. CH3COOH or O2NCH2COOH b. Cl2CHCH2OH or Cl2CHCH2CH2OH

The C H bond in acetone, (CH3)2C O, has a pKa of 19.2. Draw two resonance structures for its conjugate base. Then, explain why acetone is much more acidic than propane, CH3CH2CH3 (pKa = 50).

Acetonitrile (CH3CN) has a pKa of 25, making it more acidic than many other compounds having only C H bonds. Draw Lewis structures for acetonitrile and its conjugate base. Use resonance structures to account for the acidity of acetonitrile.

For each pair of compounds: [1] Which indicated H is more acidic? [2] Draw the conjugate base of each acid. [3] Which conjugate base is stronger? a. CH3CH2 C C H or CH3CH2CH2CH2 H b. H or H H

Rank the compounds in each group in order of increasing acidity. a. CH3CH2CH3, CH3CH2OH, CH3CH2NH2 b. BrCH2COOH, CH3CH2COOH, CH3CH2CH2OH c. CH3CH2NH2, (CH3)3N, CH3CH2OH

Which proton in each of the following drugs is most acidic? THC is the active component in marijuana, ketoprofen is an anti-infl ammatory agent, and propranolol is an antihypertensive agent that is, it lowers blood pressure. a. O OH THC tetrahydrocannabinol b. O COOH ketoprofen c. O OH N H propranolol

Draw the products formed when 2-propanol [(CH3)2CHOH], the main ingredient in rubbing alcohol, is treated with each acid or base: (a) NaH; (b) H2SO4; (c) Li+N[CH(CH3)2]2; (d) CH3CO2H.

Compounds like amphetamine that contain nitrogen atoms are protonated by the HCl in the gastric juices of the stomach, and the resulting salt is then deprotonated in the basic environment of the intestines to regenerate the neutral form. Write proton transfer reactions for both of these processes. Where is amphetamine likely to be absorbed by the body?

Which compounds are Lewis bases? a. NH3 b. CH3CH2CH3 c. H d. H C C H

Which compounds are Lewis acids? a. BBr3 b. CH3CH2OH c. (CH3)3C+ d. Br

Draw the products of each reaction, and label the nucleophile and electrophile. a. CH3CH2 O CH2CH3 + BBr3 b. C O CH3 CH3 + AlCl3

Draw the product formed when (CH3CH2)3N:, a Lewis base, reacts with each Lewis acid: (a) B(CH3)3; (b) (CH3)3C+ ; (c) AlCl3.

Label the Lewis acid and base. Use curved arrow notation to show the movement of electron pairs. CH2 C + H3O+ + H2O CH3 H CH3 C CH3 H

What is the conjugate acid of each base? a. H2O b. NH2 c. HCO3 d. CH3CH2NHCH3 e. CH3OCH3 f. CH3COO

What is the conjugate base of each acid? a. HCN b. HCO3 c. (CH3)2 + NH2 d. HC CH e. CH3CH2COOH f. CH3SO3H

Draw the products formed from the acidbase reaction of H2SO4 with each compound. a. OH b. NH2 c. OCH3 d. N CH3

Draw the products formed from the acidbase reaction of KOH with each compound. a. OH b. OH O c. C CH d. CH3 OH

Draw the products of each proton transfer reaction. Label the acid and base in the starting materials, and the conjugate acid and base in the products. a. CH3OH + NH2 d. (CH + H Cl 3CH2)3N b. CH3CH2 C O O H + CH3O e. CH3CH2 O H + H Br c. CH3CH2 CCH + H f. CH3C C + H2O

Draw the products of each acidbase reaction. a. COOH + NH3 d. CH3CH2 OH + KOH b. CF3 C O OH + NaHCO3 e. (CH3)2NH + CH3 SO3H c. CH3 C H C + NaNH2 f. O C CH3 CH3 + H2SO4

Draw the products of each acidbase reaction. a. H CH3 CH3O COOH NaOH naproxen anti-inflammatory agent + b. H CH2CH2NHCH3 O CF3 HCl fluoxetine antidepressant

Fenfluramine and phentermine are two components of fenphen, an appetite suppressant withdrawn from the market in 1997 after it was shown to damage the heart valves in some patients. What products are formed when fenfl uramine and phentermine are each treated with acetic acid (CH3CO2H)? CH2CH(CH3)NHCH2CH3 CH2C(CH3)2NH2 fenfluramine phentermine CF3

What is Ka for each compound? Use a calculator when necessary. a. H2S b. ClCH2COOH c. HCN pKa = 7.0 pKa = 2.8 pKa = 9.1

What is the pKa for each compound? Use a calculator when necessary. a. CH2NH3 Ka = 4.7 1010 + b. NH3 Ka = 2.3 105 + c. CF3COOH Ka = 5.9 101

Which bases in Table 2.1 are strong enough to deprotonate each compound? a. H2O b. NH3 c. CH4

Which of the following bases are strong enough to deprotonate CH3CH2CH2C CH (pKa = 25), so that equilibrium favors the products: (a) H2O; (b) NaOH; (c) NaNH2; (d) NH3; (e) NaH; (f) CH3Li?

Which compounds can be deprotonated by OH, so that equilibrium favors the products? Refer to the pKa table in Appendix A. a. HCOOH b. H2S c. CH3 d. CH3NH2

Draw the products of each reaction. Use the pKa table in Appendix A to decide if the equilibrium favors the starting materials or products. a. CF3 C O OH + OCH2CH3 d. OH + NaHCO3 b. CH3CH2 C O OH + NaCl e. H C H + Li+ C CH2CH3 c. (CH3)3COH + H2SO4 f. CH3NH2 + H2SO4

Rank the following compounds in order of increasing acidity. a. NH3, H2O, HF e. CH3OH, CH3NH2, CH3CH3 b. HBr, HCl, HF f. HCl, H2O, H2S c. H2O, H3O+ , HO g. CH3CH2CH3, CICH2CH2OH, CH3CH2OH d. NH3, H2O, H2S h. HC CCH2CH3, CH3CH2CH2CH3, CH3CH CHCH3

The pKas of the two ammonium cations drawn below are 8.33 and 11.1. Which pKa corresponds to which cation? Explain your choice. NH2 O + NH2

Explain why the pKa of propiolic acid (HC CCO2H, pKa = 1.8) is signifi cantly lower than the pKa of propanoic acid (CH3CH2CO2H, pKa = 4.9).

The pKa of three different C H bonds is given below. CH3CH2CH2 H CH2 C CH3 CH2 H O C CH3 CH2 H pKa = 50 pKa = 43 pKa = 19.2 a. For each compound, draw the conjugate base, including all possible resonance structures. b. Explain the observed trend in pKa.

a. What is the conjugate acid of A? b. What is the conjugate base of A? H2N OH A

Many drugs are BrnstedLowry acids or bases. a. What is the most acidic proton in the analgesic ibuprofen? Draw the conjugate base. b. What is the most basic electron pair in cocaine? Draw the conjugate acid. COOH ibuprofen N OCH3 CH3 O O O cocaine

The pKa of nitromethane (CH3NO2) is 10, making its C H bond more acidic than most C H bonds. Explain.

Dimethyl ether (CH3OCH3) and ethanol (CH3CH2OH) are isomers, but CH3OCH3 has a pKa of 40 and CH3CH2OH has a pKa of 16. Why are these pKa values so different?

Atenolol is a (beta) blocker, a drug used to treat high blood pressure. Which of the indicated N H bonds is more acidic? Explain your reasoning. O OH atenolol N O N H H H

Ethyl butanoate, CH3CH2CH2CO2CH2CH3, is one of the many organic compounds isolated from mangoes. Which hydrogen is most readily removed when ethyl butanoate is treated with base? Propose a reason for your choice, and using the data in Appendix A, estimate its pKa.

Label the three most acidic hydrogen atoms in lactic acid, CH3CH(OH)CO2H, and rank them in order of decreasing acidity. Explain your reasoning.

Classify each compound as a Lewis base, a BrnstedLowry base, both, or neither. a. H H O C b. CH3 Cl c. d.

Classify each species as a Lewis acid, a BrnstedLowry acid, both, or neither. a. H3O+ b. Cl3C+ c. BCl3 d. BF4

Label the Lewis acid and Lewis base in each reaction. Use curved arrows to show the movement of electron pairs. a. + Cl B Cl Cl Cl Cl BCl3 c. O C CH3 Cl OH CH3 C Cl OH O + b. + H2SO4 + H + HSO4 CH3 CH3 C CH3 CH3 C CH3 CH3 C C CH3 CH3

Draw the products of each Lewis acidbase reaction. Label the electrophile and nucleophile. a. CH3CH2OH BF + 3 c. C CH3 CH3 O + BF3 e. FeBr Br2 + 3 b. CH3SCH3 AlCl + 3 d. + H2O

Draw the product formed when the Lewis acid (CH3CH2)3C+ reacts with each Lewis base: (a) H2O; (b) CH3OH; (c) (CH3)2O; (d) NH3; (e) (CH3)2NH.

Classify each reaction as either a proton transfer reaction, or a reaction of a nucleophile with an electrophile. Use curved arrows to show how the electron pairs move. a. OH HBr OH2 Br Br + + H2O + + b. HBr Br Br + + + c. H H Br+ H H Br Br H + HBr Br

Hydroxide ( OH) can react as a BrnstedLowry base (and remove a proton), or a Lewis base (and attack a carbon atom). (a) What organic product is formed when OH reacts with the carbocation (CH3)3C+ as a BrnstedLowry base? (b) What organic product is formed when OH reacts with (CH3)3C+ as a Lewis base?

Answer the following questions about esmolol, a drug used to treat high blood pressure sold under the trade name Brevibloc. O N CH3O OH H O esmolol a. Label the two most acidic hydrogen atoms in esmolol, and explain which H is more acidic. b. What products are formed when esmolol is treated with NaH? c. What products are formed when esmolol is treated with HCl? d. Label all sp2 hybridized C atoms. e. Label the only trigonal pyramidal atom. f. Label all Cs that bear a + charge.

Two pKa values are reported for malonic acid, a compound with two COOH groups. Explain why one pKa is lower and one pKa is higher than the pKa of acetic acid (CH3COOH, pKa = 4.8). HO OH O O pKa = 2.86 HO O O O O O O O pKa = 5.70 malonic acid

Amino acids such as glycine are the building blocks of large molecules called proteins that give structure to muscle, tendon, hair, and nails. NH2CH2 glycine C O OH NH3CH2 C O O zwitterion form + a. Explain why glycine does not actually exist in the form with all atoms uncharged, but actually exists as a salt called a zwitterion. b. What product is formed when glycine is treated with concentrated HCl? c. What product is formed when glycine is treated with NaOH?

Write a stepwise reaction sequence using proton transfer reactions to show how the following reaction occurs. (Hint: As a fi rst step, use OH to remove a proton from the CH2 group between the C O and C C.) OH H2O (solvent) O

Which H atom in vitamin C (ascorbic acid) is most acidic? O O HO OH HO OH vitamin C ascorbic acid