MolSynapsequestion bank

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

JEE Main levelOne or more correct optionsDifficulty 2 of 3o1018

Using the rule that a good leaving group is the conjugate base of an acid with pKa below 0, select the good leaving group(s). Data: pKa of $HCl$ -7; of $CH X_{3} SO X_{3} H$ -1.9; of $HCN$ 9.2; of $HF$ 3.2.

A $Cl X^{-}$
B $CH X_{3} SO X_{3} X^{-}$
C $CN X^{-}$
D $F X^{-}$

Answer: A, B

Only HCl (-7) and

CH X_{3} SO X_{3} H

(-1.9) have pKa below 0, so

Cl X^{-}

and mesylate are good leaving groups. HCN (9.2) and HF (3.2) are too weak as acids, so

CN X^{-}

and

F X^{-}

are poor leaving groups.

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

Following the NCERT convention, ethyl bromide is treated separately with (P) KNO2 and (Q) AgNO2. The main products are respectively JEE Main level
Which carbonyl carbon is the most electrophilic? JEE Main level
Count the ambident nucleophiles in the following list. Counting convention: a species is ambident if it has two different kinds of atoms (di... JEE Main level
Which of the following species can act as electrophiles? JEE Main level
Which of the following is a good nucleophile but a very weak base? JEE Main level
Compared with ethoxide, (CH3)3C-O- is JEE Main level