Left and right hand are chiral because their mirror image are non superimposable even propan-2-ol mirror image is non superimposable then how come is it achiral ?

Objects which are non-superimposable on their mirror images are called chiral and the property of non-superimposability is called chirality while those which are superimposable on their mirror images are called achiral .

Propan-2-ol is an achiral molecule because its mirror image is superimposable.


Thus as clear in the diagram, mirror images of propan-2-ol are superimposable. Thus it is achiral molecule.