Chemistry Chirality: why these molecules are not chiral?

[tsuwal]

Homework Statement

Look at the image please. The image shows 3 pairs of compounds. Explain why the first two are not chiral but the last one is chiral.

Homework Equations

Ar means Aromatic ring

Aquirais means aquiral
Quirais means chiral

The Attempt at a Solution

A chiral carbon is linked to four different groups of atoms. However, this doesn't happen in any of them.

 

[tiklu123]

A chiral molecule need not have a chiral carbon..morever a molecule having more than one chiral carbons may not be chiral...The only necessary condition for a molecule to be chiral is non superimposability on its mirror image...try making mirror images of the given compounds and try to superimpose them on each other using your mind...this method works well for such simple compounds

 

[tsuwal]

Thanks!