91Ó°ÊÓ

A molecule is said to be chiral if it is not superimposed by its mirror image, i.e., not identical in all respects. On the other hand, a molecule is said to be non-chiral or achiral if it is exactly superimposed by its mirror image, i.e., an identical image.

The tennis ball can form superimposed images. Hence, the tennis ball is non-chiral.

The screw mirror images cannot be imposed on one another. Hence, a screw is chiral.

The mirror image of the page is superimposable. Hence, this page is non-chiral.

The mirror image of a snowflake is superimposable. Hence, a snowflake is non-chiral.

The spiral staircase has a symmetry line that cannot be easily superimposed. Hence, a spiral staircase is chiral.

The right shoe and the left shoe are not superimposable. Hence, a shoe is chiral.

Thus, glove, screw, spiral staircase, and shoe are chiral objects, and tennis ball, page, and snow flake are non-chiral objects.