The condition for skidding is

Explanation

(i) A carbon atom whose. tetravalency in satisfied by four different substituents (atoms (or) groups) is called asymmetric carbon (or) chiral carbon. The optical isomer should have one or more chiral carbon to show optical activity
(ii) The molecule possessing chiral carbon atom and is non-superimposable its own mirror image is said to be chiral molecule and the property is called chirality or dissymmetry.
`underset("Assymetric carbon atom")(d-underset(x)underset(|)overset(a)overset(|)C-b)`