Acetone has pK_a = 19.3. Conjugate-acid pK_a values: ethanol 15.9, H2 35, diisopropylamine 36, NH3 38. Which bases convert acetone essentially completely into its enolate (take log K geq 4)?

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3g2165

Acetone has $p K_{a} = 19.3$ . Conjugate-acid $p K_{a}$ values: ethanol 15.9, $H X_{2}$ 35, diisopropylamine 36, $NH X_{3}$ 38. Which bases convert acetone essentially completely into its enolate (take $lo g K \geq 4$ )?

lo g K

NaOEt

= 15.9 - 19.3 = - 3.4

;

NaH

= 35 - 19.3 = 15.7

; LDA

= 36 - 19.3 = 16.7

;

NaNH X_{2}

= 38 - 19.3 = 18.7

. Only the last three are strongly positive.