ch. 20

Question 1

What hybridization is the carbonyl carbon in carboxylic acids?

Answer 1

Sp2

Question 2

Are carboxylic acids weaker or stronger than mineral acids?

Answer 2

weaker

Question 3

Why do carboxylic acids dissociate more than alcohols?

Answer 3

the carboxylate ions are stablized by resonance

Question 4

What is the pKa of carboxylic acids?

Answer 4

Approximately 5

Question 5

What makes carboxylic acids more acidic?

Answer 5

Being substituted by EWG lowering the pKa and stabilizing the carboxylate ions.

Question 6

What makes a carboxylic acid less acidic?

Answer 6

Being substituted by EDG raising the pKa and destabilizing the carboxylate ions.

Question 7

Henderson-Hasselbalch Equation

Answer 7

pH = pK_a + log10([A^-] / [HA])

Question 8

What pH causes carboxylic acids to entirely dissociate?

Answer 8

pH= 7.3; exist as carboxylate anions

Question 9

Methods of synthesis of carboxylic acids?

Answer 9

Oxidation of alkylbenzenes, oxidation of primary alcohols/aldehydes, reaction of Grignard reagents with CO2 (carboxylation), and hydrolysis of nitriles

Question 10

General reactions of carboxylic acids?

Answer 10

Loss of acidic proton, nucleophilic acyl substitution at the carbonyl group, substitution of the alpha carbon, and reduction.

Question 11

Nitriles are prepared by what type of reactions?

Answer 11

SN2 reaction of alkyl halide with cyanide ion or dehydration of an amide

Question 12

Reactions of nitriles

Answer 12

hydrolysis to carboxylic acids, reduction to primary amines, and reaction with Grignard reagents to yield ketones

Question 13

Acids IR absorption?

Answer 13

2500-3300 cm O-H bond and 1710-1760 cm C=O

Question 14

Nitriles IR absorption?

Answer 14

2250 cm

Question 15

Acids CNMR and HNMR absorption?

Answer 15

165-185 and 12

Question 16

Nitriles CNMR absoprtion

Answer 16

115-130