Exams › JEE Advanced › Chemistry

How many of the following compounds are more acidic than ethanol (CH3-CH2-OH)? (a) CF3-CH2-OH (2,2,2-trifluoroethanol) (b) CH3-CF2-OH (1,1-difluoroethanol) (c) CH3-C(=O)-OH (acetic acid) (d) CH3-CH(OH)-CH3 (propan-2-ol)

1. (a) CF3-CH2-OH
2. (b) CH3-CF2-OH
3. (c) CH3-C(=O)-OH
4. (d) CH3-CH(OH)-CH3

Correct answer: (c) CH3-C(=O)-OH

Solution

Compounds (a), (b), and (c) are all more acidic than ethanol: (a) CF3 withdraws electrons strongly, (b) CF2 provides moderate inductive withdrawal, (c) acetic acid is a carboxylic acid (resonance-stabilised conjugate base, pKa ~4.75 vs ~16 for ethanol). Isopropanol (d) is comparable to or slightly less acidic than ethanol. Three compounds qualify.

Related JEE Advanced Chemistry questions

• The transformation of C2H5CON to C2H5NCO demonstrates a rearrangement involving the migration of an alkyl group to which site?
• The hyperconjugative stabilities of tert-butyl cation and 2-butene, respectively, are due to -
• How many valid pairs (P1, P2) are possible such that 'P1-methylpent-P2-yne' is a correct IUPAC name, where P1 denotes the position of the methyl substituent and P2 denotes the position of the triple bond?
• In the Reimer-Tiemann reaction (phenol + CHCl3 + NaOH, heated), which intermediate is formed on the pathway to salicylaldehyde?
• How many of the following groups show a negative inductive (-I) effect? (a) -Cl (b) -CH3 (c) -O(-) (d) -COO(-) (e) -CMe3 (f) -F (g) -NH2 (h) -OH (i) -NO2 (j) -N=O (k) (+)-NH3
• How many of the following groups show the -I (negative inductive) effect? (a) -Cl, (b) -CH3, (c) -O⁻, (d) -COO⁻, (e) -CMe3, (f) -F, (g) -NH2, (h) -OH, (i) -NO2, (j) -N=O, (k) -NH3⁺

⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →