CARBOXYLIC ACIDS 503 19.2 Ionization of peroxy acids such as peroxyacetic acid yields an anion that cannot be stabilized by res not possible is sanborn group is 19.3 Recall from Chapter 4(text Section 4.6) that an acid-base equilibrium favors formation of the weaker acid and base. Also remember that the weaker acid forms the stronger conjugate base, and vIce versa (b) The acid-base reaction between acetic acid and tert-butoxide ion is represented by the equatio CHiCO,H +(CH3)3CO CH3 CO, +(CH3)COH Acetic acid tert-Butoxide Butyl alcohol (stronger acid) (stronger base) (weaker base) Icohols are weaker acids than carboxylic acids; the equilibrium lies to the right. (c) Bromide ion is the conjugate base of hydrogen bromide, a strong acid CH CO,H+ CH3CO2 HBI Acetic acid Bromide ion Acetate ion Hydrogen (weaker base) In this case, the position of equilibrium favors the starting materials, because acetic acid is a weaker acid than hydrogen bromide (d) Acetylide ion is a rather strong base, and acetylene, with a k of 10, is a much weaker acid than acetic acid. The position of equilibrium favors the formation of products CH2COH+HC≡C CH2CO3+HC≡CH (stronger acid) (stronger base) eaker base) (weaker acid (e) Nitrate ion is a very weak base; it is the conjugate base of the strong acid nitric acid. The position of equilibrium lies to the left CH3CO,H HNO Acetic acid Nitrate ion Acetate ion Nitric acid (weaker acid weaker base) (f) Amide ion is a very strong base; it is the conjugate base of ammonia, pKa= 36. The position of equilibrium lies to the right. CH,CO,H H,N CHCO Amide ion Ammonia (stronger base) (weaker base (weaker acid Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE WebsiteCARBOXYLIC ACIDS 503 19.2 Ionization of peroxy acids such as peroxyacetic acid yields an anion that cannot be stabilized by res￾onance in the same way that acetate can. 19.3 Recall from Chapter 4 (text Section 4.6) that an acid–base equilibrium favors formation of the weaker acid and base. Also remember that the weaker acid forms the stronger conjugate base, and vice versa. (b) The acid–base reaction between acetic acid and tert-butoxide ion is represented by the equation Alcohols are weaker acids than carboxylic acids; the equilibrium lies to the right. (c) Bromide ion is the conjugate base of hydrogen bromide, a strong acid. In this case, the position of equilibrium favors the starting materials, because acetic acid is a weaker acid than hydrogen bromide. (d) Acetylide ion is a rather strong base, and acetylene, with a Ka of 1026, is a much weaker acid than acetic acid. The position of equilibrium favors the formation of products. (e) Nitrate ion is a very weak base; it is the conjugate base of the strong acid nitric acid. The position of equilibrium lies to the left. ( f ) Amide ion is a very strong base; it is the conjugate base of ammonia, pKa 36. The position of equilibrium lies to the right. CH3CO2H  Acetic acid (stronger acid) H2N Amide ion (stronger base) CH2CO2  Acetate ion (weaker base) NH3 Ammonia (weaker acid) CH3CO2H  Acetic acid (weaker acid) NO3 Nitrate ion (weaker base) CH3CO2  Acetate ion (stronger base) HNO3 Nitric acid (stronger acid) CH3CO2  Acetate ion (weaker base) Acetylene (weaker acid) CH3CO2H  HC CH Acetic acid (stronger acid) Acetylide ion (stronger base) HC C CH3CO2H  Acetic acid (weaker acid) Br Bromide ion (weaker base) CH3CO2  Acetate ion (stronger base) HBr Hydrogen bromide (stronger acid) Acetic acid (stronger acid) tert-Butoxide (stronger base) tert-Butyl alcohol (weaker acid) CH3CO2H (CH3)3CO Acetate ion (weaker base) CH3CO2 (CH3)   3COH Delocalization of negative charge into carbonyl group is not possible in peroxyacetate ion. CH3CO O O __ __ __ Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website