Question

10. In the following molecule, the chiral center(s) are at: 02 OCH2CH3 CH,COOH (a) a (c) C (d) d (e) e What is the most basic functional group in the molecule?

Answer 1

A chiral centre in a molecule is identified as a sp³ hybridised atom i.e. a tetrahedral atom that is bonded to four different groups. Let's examine the given choices one by one.

a.

O OCH2CH2 CH2COOH

Here the centre 'a' denotes a carbon which is triangular planar. Since it isn't tetrahedral, it is NOT a chiral centre.

b.

OCH2CH3 IW Нооочно

The centre labeled 'b' is tetrahedral and the four groups (H is not highlighted in the original structure) are different. Hence this centre is a chiral centre.

c.

HOʻноо CH2COOH

The center labeled 'c' is tetrahedral and the four groups are different. The closed ring formed at center 'c' is asymmetrical as we can see the atoms labelled 1 and 1' are different. So we consider both branches as different groups. Hence this center is a chiral center.

d.

LOCH2CH3 os CH2COOH

The center labeled 'D' is tetrahedral and the four groups are different. The closed ring formed this center is asymmetrical as we can see the atoms labelled 1 and 1' are different. So we consider both branches and the lone pair on N as different groups. Hence this center is a chiral center.

e.

0= OCH2CH3 1 IN CH2COOH

The centre labeled 'e' is tetrahedral but two identical methyl groups. Hence this centre is NOT a chiral centre.

The most basic group in the molecule is labelled as follows:

LOCH2CH3 ZSI CH2COOH most basic functional group

The labelled nitrogen is the most basic as it has most electron density.