Q3P. Question: Rank the compounds in ... [FREE SOLUTION]

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Chapter 20: Q3P. (page 1047)

Question: Rank the compounds in each set in order of increasing acid strength.
(a) ${CH}_{3} {CH}_{2} COOH$ , ${CH}_{3} CHBrCOOH$ , ${CH}_{3} {CBr}_{2} COOH$
(b) ${CH}_{3} {CH}_{2} {CH}_{2} CHBrCOOH$ , ${CH}_{3} {CH}_{2} {CHBrCH}_{2} COOH$ , ${CH}_{3} {CHBrCH}_{2} {CH}_{2} COOH$
(c)
, ${CH}_{3} {CH}_{2} COOH$ ,

Short Answer

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(a)

(b)

(c)

Step by step solution

Acid strength

Acidic strength depends on the electron-withdrawing group; a greater number of electron-withdrawing groups increases the acidity of a compound.The electron-withdrawing group stabilizesthe carboxylate anion.

Order of increasing acid strength

(a) The greater the number of electron-withdrawing substituents present in the compound, the morethe carboxylate ion will stabilize. So, the compound with two bromine groups has the strongest acidic strength.

Order of increasing acid strength

(b) The closer the electron-withdrawing substituents are to the carboxyl group, the greater will be the stabilization of the carboxylate ion. So, the compound with the bromine group closer to the carboxyl group has the strongest acidic strength.

Order of increasing acid strength

(c) The stronger the electron-withdrawing group, the greater the carboxylate ion's stabilization is. So, the compound with the nitro group has the strongest acidic strength because it is the strongest electron-withdrawing group.