Take pK_a: H2 35, phenol 10.0, ethanol 15.9, ethyne 25, NH3 38. For which of the following is deprotonation by NaH thermodynamically unfavourable (log K < 0)?

JEE Main levelSingle correct optionDifficulty 2 of 3g2164

Take $p K_{a}$ : $H X_{2}$ 35, phenol 10.0, ethanol 15.9, ethyne 25, $NH X_{3}$ 38. For which of the following is deprotonation by $NaH$ thermodynamically unfavourable ( $lo g K < 0$ )?

lo g K = 35 - p K_{a} (acid)

: phenol

25

, ethanol

19.1

, ethyne

10

, all positive. For ammonia

lo g K = 35 - 38 = - 3

, so

NaH

cannot deprotonate it appreciably.