MolSynapsequestion bank

MolSynapse / Question bank / Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition / Electrophiles, nucleophiles, nucleophilicity and leaving groups

NEET levelSingle correct optionDifficulty 1 of 3o1003

Which of the following is the poorest leaving group?

A $OH X^{-}$
B $Br X^{-}$
C $Cl X^{-}$
D $CH X_{3} SO X_{3} X^{-}$

Answer: A

Leaving ability parallels the acidity of the conjugate acid. Water has pKa about 15.7, while HCl, HBr and

CH X_{3} SO X_{3} H

are strong acids (pKa below 0).

OH X^{-}

is a strong base and therefore the poorest leaving group.

Practice Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition More on Electrophiles, nucleophiles, nucleophilicity and leaving groups

Previous questionNext question

More questions on Electrophiles, nucleophiles, nucleophilicity and leaving groups