Question

5) Meso compounds are achiral molecules. (True or False) (0.5 point)

Answer 1

true - meso compounds are achiral molecule.

.  Explanation:

We first divide this part into 3 section to understand the whole concept easily

1. What is chiral and achiral molecule or chirality and achirality

2. What is meso Compound and achirality.

1.Chirality/Achirality :

. In general defination , In a sp3 hybridization carbon if the four group attached with it are different then it is called choral molecule.and the other hand if two of them are same then it called achiral molecule. Those carbon centre also called chiral centre or achiral centre.

A B A Chiral centre → Achiral centre. D same Chiral molecule achiral molecule

but when the number of carbon increases and structures are different ,the defination of chirality and achirality changed. Now those molecule DO NOT have plane of symmetry (PoS) and centre of symmetry (CoS) are called chiral .And those molecule have atleast one of them PoS or CoS or both are called achiral.Plane of symmetry can be imagined as a plane that cut a molecule in way that it looks same in both side.like a mirror image .Example if you cut your notebook in the middle then two parts are look like same . This thing also applied in molecule.

. Centre of symmetry is point from where if you go opposite direction in same length you will get same environment.image a piece of A4 paper and you mark above two corner A A and bottom of two corner A A in a sequence . Now you will get a CoS and also PoS in A4
A > (105) A4 paper AL A pos (Plane of symmetry
paper .

the optical activity (light sensitive) is depend upon the the this PoS and CoS.

. 2. Meso compound and achirality:

. Meso compound is set of isomer which in general optical inactive although it has a chiral centres .What that mean we discussed early that four different groups or same groups are not the only factor for chirality ir achirality . If molecule having a carbon centre with different four groups but it also have atleat a POS or CoS or both then overall molecule called achiral molecule.

. The meso compound has that factor and it is achiral. Example will be better for understanding.

. Take a meso compound  

.   
dellin GH5 Chiral centre cats H H H (Etat TH H CH) I * (pos) (POS) SHO Chiral centre. CHats meso compound.
here in this compounds there has two chiral centre (* marks ) but POs is present so overall achiral and optically active.

So, it prove that meso composed always achiral.

Hope you understand the basic .Thank you

.

​